Against sejuani, Once Sejuani hits level 6, her kill pressure increases dramatically as her Ultimate R is a great ganking tool. Expect her to gank whenever her Ultimate R is up.

As soon as Sejuani has completed her jungling item, it will be difficult for you to kill her as she will be rather tanky. Avoid fighting her at this time unless you have an advantage.

Sejuani is really good during the mid and late game as she can catch players out in a team fight with her Ultimate R. Watch your positioning so she cannot isolate you and start the team fight. Against sejuani, Once Sejuani reaches level 6, her death pressure increases significantly as her Ultimate R is an excellent inflation tool. Expect that she will inflate every time her Ultimate R is in place. As soon as Sejuani finishes her juggling, it will be difficult for you to kill her because she will rather be tanky. Avoid fighting her at that time unless you have an advantage. Sejuani is really good during the middle and end of the game because she can catch the players in a team fight with her Ultimate R. Look at your positioning so she can't isolate you and start the team fight.