Rogue Galaxy Quarry: The Sin-Steeped Drifter
The closest teleport point to the Sin-Steeped Drifter is Path to Burkaqua - Creekside. Once you arrive here you'll want to head in the opposite direction of the weird guy's house whom you met earlier in the game. You'll want to head all the way down to the dead end following the river and then circle back up across the dead tree in order to reach a little cove with a waterfall. In here you'll find the circle to summon the boss.
If you are missing the item required to summon this boss grind some battles and cross your fingers or go treasure chest hunting on a planet you've 100% the map on. In Rogue Galaxy once you pass a certain chapter the loot table of items that can drop for you ingame is updated.
What I mean is, every item has a chance of dropping off every creature after you've passed that chapter that allows that item to drop. At least this is how it works in my experience. Therefore, if you're missing any items to summon any of the quarry bosses all you need to do is grind a little until you get that item to drop for you. Good luck!