User blog comment:PhaseblastSnatchNlvlcap'd/It's So Unfair!/@comment-2207030-20120517154147

LVL 15 is the minimum lvl required to start the Prove Yourself mission in the Underdome. Enemies will always be at your level, no matter what playthru you are attempting it at.

If you are truely set on attempting the Underdome with an advantage, try splittscreening with 2nd profile character that is lower level than the one you wish to do the "challenge" with.

However, making sure you have a high level weapons, shields, coms and Skills is more than enough to survive the Prove Yourself mission solo. Also, try to make good use of the surroundings. I have found spots in every arena that provide good cover and attack points. A little trial and error effort is all that is needed to find and use these spots to you advantage.