Re: RPG Maker Hentai Games
He is the guy in the tiny shack in the slums (just as you enter), you can get in by grabbing a key off the corpses floating in the water.
Costs 500 gold to accompany you per trip.
No no, that's the right house but the corpse give the key to the other house, where there's a lady selling stat boosting items (as well as lust increasing/reducing item)
Nils become available once you get the tentacle mission, your guild master will mention he's knowledgable or something like that.
After you get the mission, once you go inspect the door you'll get a conversation and then he'll ask whether you want to pay (you can choose to not take him along, once you get the triple strike (20MP) sword skill and at least 1 hit-all magic attack, just using 2 double attack armlets will easily let you kill everything while you still have MP)
Another location I think most people haven't check is Babel Tower
You get to it by stepping into the magic circle behind the counter in the guild hall.
If I read the readme correctly, each floor is lv 10 * floor number, but there's also some great loot to be found there too.