Ryuk says:
（仮にも死神である俺を恐れることもなく、媚びることもなく、こういうことに関してはガンガン突っ込んでくる）
 (Although I may not be perfect as a Shinigami) I am a Shinigami, but he is not afraid of me...
 *仮にも is a tricky set phrase, but it roughly means "despite being imperfect", "like it or not", etc. It's used
  to emphasize a cold fact, and it has nothing to do with hypothesis.
  (from:https://japanese.stackexchange.com/questions/62961/meaning-of-%E8%BA%AB-%E6%9C%AB-and-%E4%BB%AE%E3%81%AB)
The author of the blog says:
 いやリューク、アンタ仮にじゃなくて正真正銘混じりっけ無し純度100％の死神だろ。
 Well Ryuk, even if you aren't/weren't (a shinigami) (you) look like a 100% real shinigami