Rain of Arrows should have been named rain. A resource, an exhaust, and a keyword restriction for just one damage per enemy for one player? Even Skyward Volley and Hail of Stones are better than this.
Rain of Arrows
Event. Cost: 1.
Action: Exhaust a character you control with the ranged keyword to choose a player. Deal 1 damage to each enemy engaged with that player.
Arrows thick as the rain came whistling over the battlements, and fell clinking and glancing on th estones. Many found their mark. The Two Towers
Core Set #33. Tactics.