Sejuani is a SLOW and Stun tank, although she can do some great AoE damage, therefore increasing her ability to slow and harass making her a great teammate.

Pros - This build making her very tanky agains avrg AD champions and making the rest very easy to kill with slows and stuns with the item effects.

cons - This build making ur physical attack pretty low and you won't be able to do stuff on your own in battle unless you drain properly mana, mostly with W>Q>E combo.