Bonus Action: if either of the attacks was a critical hit or reduced a creature to 0 HP, the Great Weapon Master feat allows him to make an extra attack as a bonus action. GWM extra attack: 30, Damage: 30 (thunder) + 17 (force) = 47 (total)
It takes all three hits, but the wraith falls to your attack. This leaves one, plus the necromancer
[[ OOC: @Aaggie - In that case, the sword wraith should still be alive...er...not quite dead?...only mostly dead? That is, the swrord wraith should still be UNdead. Tyekanik's extra bonus action attack only happens if one of Tyekanik's two attacks (from the attack action) was a critical hit or was a hit that reduced an opponent to 0 HP. Since neither attack was a critical hit, he didn't get to make that Bonus Action attack. ]]
Sparhawk will finish it off then
I will be away until Sunday night