@Crash i did by using the same Katar with Void runeword i used for the witch but it don't works because i have 15K dex, then i did a respect to see what happen and got 40K dex, this time i can hit him most of the time but still impossible to do, probably will have to skip this along with samael of course if theres no other way of doing it with the assassin.
@Orr yes, i always use dual Katars from the set because i maxed artifice or in this case one from the set and other with the runeword.
@Johnny Impak first i tried with my normal damage, 12K incinerate and 10K shockwave but he just don't die, i tried by like 30 minutes giving everything i had upon it, catalyst + incinerate + 6 shockwave + beacon all at the same time striking him without success.
Then i begin reading the skils and realized that shockwave only gives around 50% of lightning damage, the rest is physical which he is immune, so that was why he was not taking anough damage, the only way i found was getting the maximum light pierce i could get, i used all my rings, amulets and charms with -enemy light res and got 190% (including the shockwave skill).
Also keep in mind that i already had Astroga trophy, Ureh trophy, Uldyssian charm with +2 all skills and all the other charms and tropies (except the one from teganze and of course the bremmtown).
Only missing now Laz, bremmtown and spirit world, lets not talk about samael.
Please if you can kill Laz give me your solution since we are using the same build.