Yeah, he is a ***** if you don't know him. I needed 3 times on him as a level 24 tank-speced Guardian. Got him nealy the second time but all my defensive abilities where on CD. Just let Kira take him, force leap in after his knock back to interrupt his cast, dps him, run out if you feel he's going to use his knock back again shortly and leap back in after to interrupt and repeat. (I hadn't even trained stasis btw) Besides that he is doable with your defensive cds and maybe a medpack.