Dinn was a bit worried going into this fight. He knew that old mystic types tended to be canny fighters, and more physically adept then they seem, along with having powerful magic at thier beck and call. And what did Dinn have to combat this dangerous combination of intelligence, magic and years of experience? Just a strong sword, a heavy suit of armor and a warrior's resolve.
Oh yeah, and a Titan Rune.
Turns out that "more physcially adept then he seems" still isn't enough to let Zhuzhen get up from that wallop. Dinn was actually feeling a little bad for taking the fight so seriously that he may have really injured the old man. But it's all okay in the end, the DL has healers for just that sort of thing.