PROS + Incredible scaling + AOE cleanse + Great peel + Good blind pick Milio is an easy champion to start playing. He scales very well into the late game and is quite flexible as he can easily support different members of the team as opposed to Lulu who is slightly more restricted. Milio also has a safe disengage tool in his Ultra Mega Fire Kick which can peel enemies off of your teammates, but can also be used to deny jumps/dash abilities such as Elastic Slingshot and Rocket Jump. A teamwide cleanse in his Breath of Life is also an incredible tool for safety.

CONS - Squishy - Long cooldowns - Mana thirst early - Can't ult if hard CCed In the early game Milio has troubles with both long cooldowns and his small mana pool. If he gets engaged on without reacting with his Ultra Mega Fire Kick he can very easily be bursted and he can also struggle against long ranged poke as using his shields constantly will very easily eat into his mana pool. The healing on his Cozy Campfire is fairly negligible especially early on so if he gets poked he's going to stay low for a while.

SORCERY

Summon Aery is your standard enchater choice as it gives you just that little extra bit of shielding as well as some damage as well.

Manaflow Band is a great choice on Milio as he struggles with mana in the early game, however if you're planning on taking Biscuit Delivery for your mana problems then you can consider going Nimbus Cloak for some extra MS to more easily get away from divers.

Transcendence gives you haste which you need to help with the long cooldowns of Milio's spells.

While Scorch might look enticing, it's only procced if you hit your Ultra Mega Fire Kick which isn't very reliable so that's why I would rather recommend going for Gathering Storm.

RESOLVE

Revitalize gives you more healing and shielding and then you take either Bone Plating if you're against engage, Second Wind if you're against poke or Conditioning if it's a free laning phase.

INSPIRATION

Going Inspiration isn't as strong as Resolve, but it gives you Biscuit Delivery which helps Milio with his mana problems. It also gives you a bit more summoner spell and item haste from Cosmic Insight which is better than nothing, but I think going Resolve is just the stronger secondary choice.

Haste helps with Milio's long cooldowns and scales very well. If you're worried about the enemy team you can consider taking Health Scaling instead of Adaptive Force. You should also take Flat Health instead of Health Scaling in the third row if you're against an engage botlane for more safety early on.

Enchance fire with water Staff of flowing water is really good on Milio as you can easily and frequently give the movespeed buff to a lot of your teammates.

Attack speed buff Ardent censer is really gold efficient, especially when you buff your entire team with it.

Spread the love Moonstone is such a great item on enchanters as it buffs your heals and shields so much on single targets or spreads them if teammates are nearby. If you have either Ardent Censer or Staff of Flowing Water then the buffs from those items also spread.

Big teamfight heal Redemption is a great teamfight item, it helps in keeping your entire team alive during a fight. Don't be afraid of using it before a fight if you're about to take an objective.

Anti-heal Milio is one of the few enchanters that can super safely apply antiheal on the enemy team because of Fired Up! from his teammates. You shouldn't finish Morellonomicon until you have nothing else to spend money on.

Anti hard CC Mikael's Blessing can also be used on yourself just like a Quicksilver Sash in case you got stunned and can't use Breath of Life to cleanse for your entire team.

zoooom~~ If you want even more movespeed than what you're getting from Staff of Flowing Water then this is a really good active to have if your team wants a lot of movespeed to run at the enemy. Can also be used if you need to run away to fight another day.

Fired Up! Fire burns. Your passive applies an enchantment on your teammates whenever one of your skills touches them which makes their next AA deal more damage and apply a burn. (This damage safely applies your Oblivion Orb without you needing to put yourself in danger.)
Ultra Mega Fire Kick Football. Your Q kicks out a fireball that will knock back the enemy it hits a small distance, but the range is extended if hits a minion and an enemy champion is nearby. (If it passes through your teammate it also applies Fired Up! onto them.)
Cozy Campfire Attack range buff. Your W is a small healing circle that follows your targeted champion around for 6 seconds and gives everyone that was healed by it extra attack range (even if they aren't still in the circle). This is a great way of applying your Staff of Flowing Water and/or your Ardent Censer on all of your teammates.
Warm Hugs Shield. Your E is a shield and you have two charges of it. This enables you to easily shield yourself and AA the enemy in lane for a really safe trade and still having a shield ready in case they want to extend the trade.
Breath of Life AOE Cleanse. Your Ult is essentially an AOE Mikael's Blessing. When you're in the loading screen you should look at the enemy team and recognize the threats they have that you can remove using Breath of Life, e.g Wither, Nether Grasp or Enchanted Crystal Arrow and look out for them in teamfights.

Check out my other guides if you'd like!

The chain warden of botlane
Embrace the depths with Nautilus

Special thanks to jhoijhoi for their great guide to coding.