Xenoblade: The Tephra Cave Exploit

Perhaps one of Xenoblade's best-known glitches is the Tephra skip, an elaborate exploit that requires a lot of patience but allows you to reach level 50 within the first couple hours of the game. It's not infallible—while there's no cap on experience gained at a time, there is for Art and Skill Points, so you're significantly handicapping yourself on that front because of the way reward scaling works against underleveled monsters—but it makes for a neat party trick. Here's a step-by-step guide to pulling it off.
Mefimefi's basic trade table. The Block Guarder, her only item, is highlighted.
The locked door in Tephra Cave. Reyn is positioned in the right corner, and Shulk, controlled by the player, stands behind him. Arrows indicate the boys' roles and the ideal angle to squeeze yourself between Reyn and the door.
The party menu, showing the ideal setup. Reyn is in the lead with the Block Guarder equipped, and Shulk and Fiora are without armor and in their underwear.
Reyn overlooking the lake from above. Shulk, nearly dead, is fighting the Cave Skeeter on his own far below.
Reyn running into the ledge with the Cave Skeeter preparing an attack behind him.
Reyn discovers the Heavenly Window, an empty endgame area. The party has recieved 165160 EXP each, bumping them from level 8 all the way up to level 43.

From what I've heard, this skip has been fixed in Definitive Edition... which also unintentionally added a way easier way to get the same effect. I have yet to try it, but if I ever do it'll be right here on this page.

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