Rulebook page 7, under 8. Resolve Ruin:
Neither player gains the Cruelty for Culling cards this way. (For example, if 2 (ruin) was rolled, the Attacker must Cull a card with at least 2 (swords) or two cards with 1 (sword). If they only attacked with one card, it must be Culled.)
1) If you attacked with only one card with a 1 sword, you Cull that card and you're done.
2) No one gains Cruelty (no morality effect).