Tip overview

Make sure you keep track of her ultimate. It can devastate your team if it is paired with another ult.

If you pressure Seris into using her escape, turn around and listen for Seris uncloaking. Try getting someone low in the mean time, this will often cause Seris to believe she is safe since you aren't looking at her and will uncloak to heal her team.

Your shadow travel can make you immune to everything. Use it to cancel ultimates and abilities, or use it in sticky situations. (I recommend using veil since it can make you go into shadow travel faster.)

If you are playing as a front liner and Seris casts her ultimate, you can put down your shield and prevent yourself and your teammates getting pulled in, and at the same time making her waste her ult.

Her projectiles fly very slowly. It is important to dodge them so she can neither heal herself nor deal damage.