The main hazard is Damage Walls. Bring Wood Null Damage Wall monsters to deal and mitigate damage. Akagi Rin is a Demihume. Demihume and Water Slayers will make runs smooth since they deal a lot of damage Akagi Rin is a Direct Drop Quest where the Boss will drop once she is defeated. There are also 2 Mini Boss Stages where they can drop if they are defeated. However, Akagi Rin will run away in 3 Turns so you have to clear her before then. Also, the Mini Boss Stages has a chance of being skipped.