This is my first guide ever, but I've thought about making this in prior times of playing sejuani.

The purpose of this build is to utilize her abilities and tankiness, but still having an output of damage to go along with it.

Most people would recommend going Rod of Ages, but I disagree strongly with this, mostly because with cooldown reduction you can maximize her dps while having a steady chase upon opponents without losing more health than a player can afford in-game.

The way I utilize her abilities is with Magic Penetration, Cool-down Reduction, and massive amounts of health to buff her Northern Winds. Since her Northern Winds does a % of Maximum health she has. This damage buff allows her to continually apply Frost over and over again while her Permafrost nuke comes down on cooldown quick enough to allow you and your team-mates to land finishing blows. Glacial Prison her "ultimate" or "R" can be used for "Kill Securing" or stealing, Group AOE CC on their entire team, and most of all it knocks them down with frost to immediately use Permafrost and charge in with your Arctic Assault if you missed them the first time; thus applying frost to nuke with Permafrost.

Sejuani's a total movement debuff champion, and should only be used in situations where mobility is key to their team composition (anyone that gets a movement speed buff from ANY of their abilities/attacks/etc. is included).

I hope you enjoy dominating opponents with this build.

3 x Greater Quintessence of Swiftness (total: 4.5% movement speed)
9 x Greater Mark of Insight (total: 8.5 magic pent)
9 x Greater Seal of Vitality (total: 9.72 health/level; 175 health @ level 18)
9 x Greater Seal of Force (total: 1.53 ability power/level; 28 ability power @ level 18)

The movement speed quint's are for keeping up during chases and getaway

Legend
RED = Primary, YELLOW = Secondary, GREEN = Tertiary

Start:
Ruby Crystal or Boots + Potions (this part is up to whether you're comfortable with your lane)
Note 2: I usually get either 3 health potions or 2 health and 1 mana potion


1st Trip Back: (by level 3, unless you're sustaining lane like a boss)
Philosopher's Stone
Boots (if you never bought them @ level 1)
Heart of Gold


2nd Trip Back: (by level 6, and if you have money left over, finish Rylai's)
Giant's Belt or Sunfire Cape
Shurelya's Reverie
Sorceror's Boots (MP) or Mercury Treads (MR) or Tabi Boots (armor)(Counter your Enemy)

3rd Trip Back: (by level 11 - 13)
Rylai's Crystal Sceptor
Frozen Heart

4th Trip Back: (by level 18)
Sunfire Cape
Randuin's Omen or Frozen Mallet

Here are some Optional Items to Counter Enemies

Hard CC
Banshee's Veil
Quicksilver Sash

AP
Force of Nature
Athene's Unholy Grail
Wit's End
Abyssal Sceptor

AD
Randuin's Omen
Thornmail

level
1: Arctic Assault Q
2: Northern Winds W
3: Permafrost E
4: Northern Winds W
5: Northern Winds W
6: Glacial Prison R
7: Permafrost E
8: Northern Winds W
9: Northern Winds W
10: Permafrost E
11: Glacial Prison R
12: Permafrost E
13: Permafrost E
14: Arctic Assault Q
15: Arctic Assault Q
16: Glacial Prison R
17: Arctic Assault Q
18: Arctic Assault Q