Welcome to the Summoners Rift,

after that being said you already know this is your place to be as the famous "Riftwalker"; especially with this guide you will need to use movement alot so it fits even better ;).

This guide is NOT a step by step list of things you need to do, if you want to succeed with Bruiser Kassadin. I will only give you some ideas, it is up to you how you modify them to fit your own playstyle! This kind of Kassadin build is one of the most flexible and unknown (in ranks below mid diamond) builds I´ve seen in 4 years of playing League.
This means it is up to you how good it works, you´ll need to think yourself!

My name is "MaserMynd", known or not as a Platinum player. This should not scare you off, even if you are a high tier (Diamond 1+) player as I´ve understood the game better than most mid tier diamonds.
Why are you Platinum then?
Well, i´ve used to play with an MMR of Diamond 2, but i stoped playing for a bit of a longer time and I miss out alot of mechanical skills due to the lack of training them.
Are you main Toplane?
No, I am a main ADC, though i always loved to "break" the META and invent new and crazy playstyles which actually worked out (I´ve invented the Jungle Ezreal 3 weeks before it was brought to LCS, and they won with it!!).
How did you come up with this strange build?
I´ve been watching a french (ye.. i know) tournament where the Ex-Dragonborn "Spontexx" played a tanky bruiser version of Kassadin and literally crushed a whole master tier team alone. I gave it a bit of thought and came up with my own ideas on how to make this build fit my playstyle.
Is that build fix and finished?
NO!! It will never be finished, especially not in the next month or two as i just played around 20 games of Kassadin top. This is why i need YOUR INPUT to improve this guide!!

Thank you for reading through this, feel free to add me for questions and inspiration on this build or other META-breaking build ideas =) Let´s get started!

Pro´s - The "Suprise effect", enemeys won´t know what to do in lower ranks! - Good sustain in lane - Great trading potential at any stage of the game - Amazing mobility - Good splitpush potential with Teleport - A lot more tankyness than a typical Kassadin - Hybrid and constant damage due to Nether Blade - Has a good gapcloser - Great at peeling for your ADC

Con´s - Rather weak laning in the early levels - Can get bullied easily - Needs to get close to the opponent to deal damage - Is likely to get out-damaged early in longer trades - Hardly any CC

MARKS: I went for full Hybrid Pen runes. The marks are the only runes i would always use with bruiser Kassadin as you will mostly deal magic damage early game and a good mix of physical and magic damage later on (magic damage mostly through items).
GLYPHS: I am using CDR Glyphs as i prefer spamming my abilitys due to Kassadins great Mana regen with Catalyst the Protector and Nether Blade. Usually you face physical enemeys on toplane, so you will not need the magic resist in lane. Another good option would be AP-Glyphs, but they just feel weaker than CDR on this build.
SEALS: Here you have a few options: I like Armor Seals the best, but alot of Koreans are using Scalling HP Seals. I would only recommend those, if you are facing an AP enemey or you feel really safe in the early stages of the game!
QUINTS: My Movementspeed Quints are VERY VERY personal. As a main ADC I enjoy micro movement alot and so I love the extra bit of movement to dodge and outmove my enemey. They also work great along with Static Shiv. You could possible take Hybrid-Pen Glyphs or AP Glyphs. Experiment and find the ones fitting YOUR playstyle.

Spawn

In 98% times you will start with Crystalline Flask and three Total Biscuit of Rejuvenation.

Situational you could also buy Cloth Armor and five Total Biscuit of Rejuvenation or two Total Biscuit of Rejuvenation and a Stealth Ward against aggressive junglers!

First recall

This is CORE! You will need your Catalyst the Protector to ensure a proper laning phase. I would NOT recommend playing Tear of the Goddess on your first recall, though it is an option after a forced recall/death, if you can´t efford your Catalyst the Protector and you are still able to buy some Total Biscuit of Rejuvenation to ensure enough sustain in lane!

Second recall

Now you have three options:
1. Ionian Boots of Lucidity
2. Rod of Ages (Recommended in most cases
3. Tear of the Goddess (this will end in a risky Muramana buy I have not tested yet.

Further large items

Somehow essential for this build is an Iceborn Gauntlet. I would almost never choose Trinity Force over Iceborn Gauntlet as it provides some CC (and you miss that out), tankyness and on hit damage which makes your W Nether Blade amazingly powerfull! Basically the most perfect item for our interpretation of Kassadin.

Statikk Shiv is at the same time the most fun and questioned item in my build. You will be moving around the map most of the time as Kassadin barely likes Teamfights in mid-game. The extra movement from Statikk Shiv comes in very handy here. It´s passive will boost your magic damage and the attackspeed and crit chance can help you deal more consistent damage.

Banshee's Veil is a great defensive option against AP threats and Poke-teams. There is no special thought behind it.

Guardian Angel is a good choice, if teamfights extend long or you die very fast by drawing alot of attention on you (which is good, you are the tank!). With Riftwalk you will have no problem to re-engage/escape after your respawn.

Orcale's lens should be self-explaining. Use it to clear wards and to reveal champions like Akali. Against her I would recommend buying Orcale's Lens soon.

Other options

Trinity Force can replace Iceborn Gauntlet. It is a much more aggressive and 1v1 based item while being very expensive, i´d not recommend it usually.

Abyssal Mask can replace Banshee's Veil as a more aggressive option. This will boost your AP damage alot while giving you some defensive stats against AP threats.

Bloodthirster. Yes, a BT can also work on Kassadin, it has some good defensive stats with the shield along a TON of physical damage and sustain. It is again very situational as it will be hard to remain the shield, if it comes to sieges. I´d suggest to get it quite early after your Iceborn Gauntlet.

Turbo Chemtank is an option to buy, if you can´t efford a Rod of Ages early enough and you want to get more mobility for your team. It is a good item to do small trades with as it has a ton of HP-regen.

This section will be updated as soon as I have more experience with other items

Flash - Kassadin is one of the few champions who can actually not play with Flash. It is still recommended for surprising plays or escapes before you have Riftwalk. I prefer playing with it.

Barrier - This is a very defensive option, but still allows you to go for dead-or-alive trades with your lane opponent.

Heal - Just like Barrier, but a bit more aggressive. I would recommend using it, if you want to bully your enemey in the early stages alot. This works good against Rumble. !Heal is no longer recommended by me!

Exhaust - A very, very nice Summoner Spell as it lowers your enemeys damage alot while you can autoattack for free. It is also a nice tool to prevent ganks or escape better in a chase.

Teleport - There are two requirements for a TP choose over any other of the mentioned Summoner Spells: You want to splitpush later on and you don´t want to play very passively in lane. I do not like TP on Kassadin.

Ignite - I don´t like Ignite on Kassadin as i prefer one of the defensive Summoner Spells above. Playing Ignite is always a huge risk in lane!

*See the note on top for a comment on the skill order*

As we are planning to play a tanky Kassadin Void Stone is perfect for what we are trying to accomplish. Besides his ability to ignore unit collision he takes 15% less magic damage! Any "normal" Kassadin mostly uses this ability to survive in lane against AP threats. We are using this passive a lot better throughout the entire mid and late game; we can tank 15% more magic damage ! This allows us to focus more on getting decent armor and damage before buying an item for magic resist.
Null Sphere is our ranged farming tool whenever we get zoned away from the creeps. It is also our poke ability to trade in the laning phase. Our main focus is it´s ability to stop channeling skills. This means you can stop TP or certain spells like Urgot Hyper-Kinetic Position Reverser. This makes you a strong weapon against many splitpushers as you can move around the map much faster after you stoped their TP! If you are fighting against an AP threat try to use Null Sphere for it´s magic shield just before the enemey wants to use spells on you. Together with Void Stone this will block alot of incoming damage!
Nether Blade is the key to our build. It is our main damage ability as soon as you hit about level 10. Along with the boost of our Iceborn Gauntlet it is dealing terific amounts of damage. It´s passive is giving you a small but noticable boost on your normal AAs while it´s active ability boosts your next AA with magic damage and a bit more range on it. At the same time it is restoring a percentage of your missing mana. Nether Blade resets your AA, so use it directly after you hit your opponent with a normal AA to deal maximum damage. If you are fighting longer in a 1v1 situation and you need to disengage, you can step a bit away and then use one last boosted AA on your enemey with the boosted range you get from Nether Blade. This can turn a bad trade into an even trade!
Kassadin only built-in CC is Force Pulse. Even though it has a low CD, Force Pulse needs to be used carefully as it needs 6 stacks to be available again. You get one stack for each ability that is used near Kassadin. Along with CDR Kassadin can spam Force Pulse in large teamfights as there are loads of spells casted in every TF. Use it to peel for you ADC, chase down opponents, the AOE slow in TFs or in lane to poke the enemey and deny CS.

Riftwalk As riftwalk is the most complex spell of kassadin I will add this section later, please understand that. i want to create a very accurate guide!

THIS SECTION IS YET TO COME, I´ve WORKED ABOUT 7 HOURS ON THIS GUIDE NOW, I WILL UPDATE IT AS SOON AS POSSIBLE!

THIS SECTION IS YET TO COME, I´ve WORKED ABOUT 7 HOURS ON THIS GUIDE NOW, I WILL UPDATE IT AS SOON AS POSSIBLE!

I want to thank every of my enemeys and teammates for supporting me while evolving this idea of Kassadin (besides the flamers and haters, obviously ;D)!

What I want to accomplish with this guide is to make you think out of the box. I want to teach you to experiment with Masteries, Runes and Builds and not just copy what the professionals do. It´s nice to have inspriation from the pros, but always question what they did!

If you have any inspiration/tipps on this guide, please comment or add me on EUW under the summoner name "MaserMynd". I would also appreciate an upvote for this work.

If you did not like this guide please tell me in the comments what you would change. Also I´d like you to rethink a downvote. ;)

Thank you for reading through this, I hope to see more Bruiser Kassadin in the future =)