Hero Hall

The Hero Hall building is a way to enter the Hero Recruitment panel from the Town view. (It can also be entered from the Hero menu itself.) The actual Hero Hall Building (not to be confused with the Hall of Heroes event) does not have any associated building levels or upgrades.
Players can choose between two types of hero recruitment. There is Advanced Recruitment which consumes Platinum Keys (colloquially called silver keys by the Lordrush community). These can potentially provide Rare and Epic heroes, as well as Skill Books, basic resources, Speedups, and Hero XP.
Alternatively, players can choose Epic Recruitment. This consumes Gold Keys and adds Mythic heroes to the recruitment loot pool. Initially, Isabelle is the only gold key hero you can recruit, but as later generations are added, old heroes will start to make their way into the available drop as well.
All keys incrementally fill up a reward meter that allows for an additional chance at mythic heroes. In all forms of rewards, it is possible to pull hero shards or the full hero. If the full hero is unlocked, the reward will be converted into 10 hero shards.
There is no advantage to drawing 10x rewards at a time in Lordrush as this does not change the rates of the heroes being dropped like it does in gacha-style freemium games.
This building has no upgrade levels.