Rogue Galaxy Quarry: The Tomb Guardian
The closest save location to teleport to is the North Observation area in Myna. It's pretty much as far east and north as you can go in the city. This is an extremely easy fight considering it's one of the first quarries you're given. You'll still be learning the game but he should be a piece of cake for you to take down.
Since this is one of your first quarries a piece of information that you'll be happy to hear is the item required to summon the boss isn't consumed when you use it.
A Mirror Unit is required to trigger this fight. 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!