Found on the western beach in Limgrave, the Coastal Cave is dark — really dark. You’ll need a Torch or other light source. It’s fairly small, but the boss fight is the first with adds, and so can be a challenge if you aren’t prepared. Luckily, you’ve got this guide.
Before proceeding into dungeon, equip the Torch that you purchased earlier as this cave has very few sources of light (note that you can equip it in whatever hand you like, leaving your other hand free for a weapon). This dungeon is straightforward and only has a few enemies, and even fewer items.
Proceed through the cave, and deal with the enemy standing near a drop down. Do not jump down, and continue right, further through the tunnels. Once you dealt with the two enemies in the tunnel, you will arrive at a dark room with two packs of enemies. Dispose of the two weaker ones that will notice you as you enter the room, and go to the left where two enemies are sitting down. Run for a backstab on the bigger one on the left, and now all that’s left is to finish off the last enemy and proceed to the next room where the Demi-Human Chief boss fight is.
Once the boss is dead, do not take the teleport back to the entrance, instead continue down the tunnel next to it. This next tunnel has a few weak enemies, and will lead you to an island.