The idea behind this build is to help Sejuani farm faster (clear speed and movement speed) as well as increasing her dueling potential when running into enemies in the jungle. On top of that, your ganks should be more successful, as you will be able to stack your E on the enemy faster and more often.

I would generally go with Aftershock for the extra survivability as you will be a bit squishier than the usual full tank Sejuani, however your damage will also be higher and a lot of players will underestimate you.

Building into the one component of Wit's End early gives us better clearing speed, sticking power and less travel time between camps and objectives while opening up the possibility to build into magic resistance or armor depending on who seems to make the most trouble on the enemy team.

You will also be able to invade better as you spend less time in the enemy jungle and can get out faster as well and taking objectives like Heral or Drake solo will feel much less sluggish.

When facing a full AD team you can still build the component and sell it later, however in that scenario I would probably prefer to just build full tank Sejuani and maybe buy an early Bramble Vest instead.

With the other items in this build Sejuani does especially well against AP heavy comps, allowing her to build both Wit's End and Abyssal Mask, which combined with Demonic Embrace will offer quite a bit of damage.

Demonic Embrace itself is by no means a must. If I get fed (by farm or kills) I often get it to keep my damage high and stay a threat, especially if my team mates are starting to fall off in damage, however if you have a high damage team anyways, you're probably better off investing in more defensive items instead to stay alive longer, giving your team more time to make use of their damage.

Against mixed teams Wit's End will always provide some value in the early and mid game, but you could swap it out in late game for Abyssal Mask if you feel like you can't reliably autoattack in fights anymore and want to support your mage(s).

This is just a mini guide I wanted to put out there as I was trying to find a way to make Sejuani smoother and more fun to play in the early to mid game.

Clearing can feel very sluggish and enemies often get away with 3 stacks before I can trigger the E or i'm just lacking the damage to contest the enemy jungler, with this tiny adjustment to the full tank build however it feels much better and more fun to play.

I'm by no means a pro player but sporting a 62%+ Win Rate in Platinum and getting Mastery 7 at 27k points is at least an indicator for the builds success. Hope you enjoy it as much as I do. :)