The Hero 30 wiki doesn't cover this quest just yet, so:
- How can I get the Red Diamond title?
- How can I get the Ear Killer title?
The Red Diamond title is obtained by obtaining Yohei (the first town's knight) as a companion by retrieving the red diamond in the southmost cave. This is the obvious course of action, given that obtaining $1,000 for Yohei and $200 for the boat and $many to the goddess to get enough time to complete the quest is no easy feat, while leveling up enough to take the middle boss on your own probably takes more time than it saves.
The Ear Killer title, as well as the Complete status for this map, is obtained by taking a little detour to the island just south of the ship dock.