Skatrorsis is a Force affinity legendary from the Undead Hordes faction! Skartorsis is a great champion for Dungeon progression, giving a speed aura, team Buffs, team cleanse and healing and a strong AOE damage on his A1. Skartorsis has strong damage multipliers on his A1 so does get some value from Cruel gear, but could also be built tanky as a team support to keep your team moving. Other options are to put sets on him such as provoke, stun, daze to control the enemies.
If you struggle in the Arena to go first a Skartorsis in a frenzy set can be a great way to take over the lead, taking damage, moving faster and then using A3 to boost turn meter and cleanse / heal your team.