When does the secret reserve active?
We dont know for sure, but as my survey the more points you distribute the faster that skill active. Unfortunately, this skill active when low hp so if we got around 1.5k dmg before secret reserve active 90% dead. My DK could tank TP hero, but if you want more than me try your DK to tank TP hard. Current secret reserve isn't same as before, in battle mode I can heal 440hp if enemy killed we turn to normal mode and regen increased to 880hp (old system). Now in battle or normal mode have same ammount of heal. Im sure this is a bug.