Does Starcross fizzle if there is only 1 valid target remaining due to removal after cast?
No, Star-Crossed does not "fizzle" (fail entirely) if one of its targets is removed after the spell has been played and placed on the chain.
According to Rule 359.3.e.1 and Rule 359.3.e.8, spells in Riftbound resolve as much as possible even if some of their targets become illegal (e.g., if a unit is moved to a player's hand).
How it works:
- Targeting is finalized at play: You must choose two valid targets—one friendly unit and one enemy unit—when you play Star-Crossed.
- Resolution (LIFO): When Star-Crossed resolves, it checks its targets.
- If one target has been removed (e.g., returned to hand, destroyed, or moved to a non-board zone), that specific target is considered illegal and the instruction to affect it is ignored (Rule 359.3.e.5).
- If the other target is still valid (still on the board and meets the original requirements), Star-Crossed will successfully resolve for that remaining target, returning it to its owner's hand.
Summary: The spell does not fizzle. It performs its effect on any remaining valid target. This is consistent with RiftJudge FAQ #10514 and #10311.