Wow, that was crazy, from the beginning I knew that "Cheat Death" had great potential, I've been using it with the gargoyle, those seconds it gives you allow you to do an incredible amount of damage, I had also tried it with murlocs. And yesterday I faced a player who used Tyrion and your same spells, he used the griffin to level up -> tyrion, and he used the two-headed dragon, not even with my sheep spell I could stop him, he used it very intelligently "Cheat Death", and he managed to raise his tyrion to very high levels, with the help of the griffin, which made him an exceptional healer. In the end that opponent was one of the most difficult to face, my Thaurissan formation is very strong, and I was surprised how I couldn't beat him. Your formation is very scary, I hope I don't confront you hehe, At the moment I am somewhat happy because I am already over 10k points and I'm no longer afraid of facing levels higher than my level.
Its a bug, onyxia isnt supposed to reward a sigil, but early on in the games life it was rewarding players with one. They have fixed it since, but haven't taken eh additional sigil away
The double damage is when he hits something that has half HP. Though that would still be a ton of damage to the base. Mirror images are great for taunting off of grommash or huntress, and being able to cheat death the images as well and keep them alive is really strong. Something to test out for sure 😁