The cast validation demands LOS to a stone block, but the dimming aid lit every stone square on the map — including ones the caster cannot see. Now only sighted blocks light; and since the card equally targets stone walls (edges the cell-shadow cannot express), no sighted block means no shadow at all rather than a maze dimmed away from its true targets. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0138A8CjeQRpvzKxuMfz1Bqc