I don't mean to burst your bubbles but unless you want to take like 3+ hours on the raid u need all but 1 (or two if others are really good) character above lvl 26. I have a lvl 28 Titan and a lvl 29 hunter and I have attempted it with a lvl 26 character, but when I got to the last boss I was getting 1 hit by Atheon, also I think there are lvl 27s later on