For starter, the context is that we are using and developing a Treachery/Kingdom variant where each player has a special ability. One of our players on Discord asked us a question about a rules interaction that we didn't planned, and me and my co-developer cannot seem to agree on the interpretation of the card's text.
Here is the relevant rules text:
(Note: Leader just specifies one player in particular with the Leader identity, but the Leader type is not relevant in that specific case)Until end of turn, if a source, spell, or ability an opponent controls would cause a Leader player to lose life, you lose that much life instead. The same is true for discarding cards and sacrificing permanents. (Damage causes loss of life.)
Now, the question is:
Let's suppose that we are playing EDH and that someone attacks the Leader player with their commander which isn't blocked. Before the combat damages are dealt, this ability is activated. What happens with the Commander damage?
Bonus question: What happens if the Leader player is attacked by an unblocked creature with Infect?
My interpretation is that the damages are still dealt, but the life loss resulting from the Commander damage are redirected towards the controller of the ability. The Commander damage are still "marked" though and if they amount to 21 or more, the Leader player loses. Infect doesn't cause life loss and so isn't affected at all by this ability.
His interpretation is that, as long as the damage causes life loss, they are entirely redirected and do not affect the Leader player at all, which implies that Commander damage will not be marked on the Leader player, but Infect still works fine.
Which one of us is correct? Or are we both wrong?
Thank you for your help!