This is simply because not a lot of characters can fully benefit from its EM stat and passive. Still, its passive called “Bane of Storm and Tide” is actually really good. At Refinement Rank 1 (R1), it increases the wielder’s damage against opponents affected by Hydro or Electro by 20%. This damage bonus further increases with refinements – up to 36% in R5. So Rainslasher is mainly great for characters that are drafted in teams with a Hydro or Electro unit. Here’s a more detailed list of its synergy with every currently playable claymore user.
Great means that Rainslasher is one of the character’s best 4-star weapons. Good means that Rainslasher works on the character, but there are much better options (usually other 4-star claymores). Not recommended means that there are significantly better claymore options – or the character simply doesn’t benefit from Rainslasher’s stats or passive.
Rainslasher for Diluc
Rainslasher is one of Diluc’s best 4-star weapons – especially in Vaporize teams. Diluc needs a Hydro aura on the opponent to trigger a Vaporize reaction. So he’ll very often attack an opponent affected by Hydro – thus effectively activating Rainslasher’s passive. This also works in an Overvape Diluc team where opponents have both a Hydro and Electro aura on them. Rainslasher is his next best weapon option after Serpent Spine – a paywalled BP weapon. And it can even outperform some 5-star claymores like Skyward Pride and Song of Broken Pines for Diluc. Because of this, Rainslasher is highly recommended if you don’t have Serpent Spine and his other stronger 5-star weapons. It also gets better with refinements – which you’ll naturally get from pulling in gacha banners.
Rainslasher for Razor
Since the release of Dendro in 3.0, Razor has gained a notable buff with his new team. This team is composed of Razor, Bennett, Xingqiu, and Dendro Traveler. They deal damage by chaining multiple elemental reactions like Aggravate, Quicken, Spread, Burgeon, Bloom, and Hyperbloom – all of which scale from Elemental Mastery (EM). Razor triggers a sizable portion of the reactions in this team, so EM becomes a really valuable stat. Plus an Electro aura can easily stay on the opponent through Quicken. This consistently procs Rainslasher’s damage bonus passive. So Razor can effectively benefit from both Rainslahser’s EM and passive – thus making it a really powerful weapon for this team.
