If these effects cause a creature's toughness to become less than or equal to 0 or the amount of damage marked on it, those creatures die at the same time that the "legend rule" remove your excess Kaerveks
Up until now, this is a pretty obscure interaction which only came up in formats that play Urza's Saga and Blood Moon
That said, you don't need to fret about before or after combat too much
Trying to keep pace with the agro decks using pure card draw effects and efficient answers simply doesn't work, the card draw is not cost appropriately to do this
EDGE OF ETERNITIES COMMANDER: BEST NEW CARDS Of the four Commanders on offer, I feel like Hearthhull, the Worldseed has the most potential
This adds an extra aura of mystery to proceedings, and we know that having no idea whats going on brings you some more luck