So if I activate {soul conduit} with {rhox faithmender} in play, what happens?
Example:
If my opponent has 20 life and I have 10, and I activate the conduit with Roxie in play, my life total becomes 20 and I gain another 10 to be at 30, and my opponent is at 10, correct?
U r correct...;)
Correct. Life total changes with {soul conduit} are considered life gain and life loss for the sake of effects that care about such things. So your faithmender would double what you gain as you suspected.
Your opponent would also have lost 10 life in this example, for the sake of cards like {Cryptborn Horror} (X=10) and {Rakdos, Lord of Riots} (Creatures cost 10 less this turn, or life was lost so Rakdos may be cast)
Thanks!