Heimdall keeps you from dying if you would be knocked out. Hela/Angela gives you a fury buff- dash back and hold block to activate. Thor gives 15% of missing health- dash back and hold block to activate.Missing health is subject to your champs health pool. Its 15% of what's missing. You can activate the regen, fury and precision buffs at the same time by dashing back and holding block. Cheat death happens if You were going to get knocked out and leaves you at 1% health.