...Assassin!
Shield! -summons an Obsidian shield to get between himself and the strike-
-he steps back, and discards his sword for a moment- Al right...
My Heart is glass and my blood is fire- Glass flows, as magma below- It comes to pass, that it must be so- This is my story, this is my Heart's Glass!
-he puts 40% of his energy into a single and huge shard, and he's basically unleashing it point-blank as soon as Berserker gets through the shield-
-his motion kind of looks like a hadoken- Piercing shard!
1.5 imperial gallons of tea were consumed during the writing of this post▂▂▃▃▄▄▅▅! (Gae Bolg drives through the giant shard - but the splinters all get in his face, cutting him up a lot)
(as a result, he staggers the eff back, dropping Gae Bolg - Dumas can tell that not only is he bloodied, but it seems that he isn't getting any more magical energy from his Master, if Dumas can sense it)
(wounded and lethargic to the point his transcendent speed is gone, but not defeated, Berserker charges forward again, arms raised for a tackle)

-kareena looks up and spots 16-
-she gives him a big goofy grin and opens the window-
Hi 16! What are you doin' up here?
All our wishes can come true