Arsenal
The Arsenal increases Strength, which the guide says raises weapon damage, across ten upgrade levels.
How it works
The Arsenal is listed as starting at 75 gold with ten levels. It becomes available after unlocking the Valkyrie class. Its stated effect is increased Strength, raising Weapon Damage. The passage does not provide an amount of Strength or weapon damage gained per level.
Read the supporting references
A source-bounded reference to ten named Rogue Legacy 2 Manor upgrades and their described effects, prerequisites, and level counts in the IGN passage. It does not establish current patch status, exact costs beyond quoted descriptions, comparative effectiveness, or complete game coverage. Guidance explains the referenced mechanics; it is not a tested damage ranking. Check the stated edition and source version before applying a patch-specific detail.