In Memoriam Borderlands 2
Michael can be found randomly at one of several spots around Sanctuary:. Near the newsstand in Sanctuary's main plaza.
In an alley down the street from the front entrance to Moxxi's. Inside Moxxi's, near the bar. Monsters ate my birthday cake all monsters lyrics.
Inside Moxxi's, in the side room across from Sir Hammerlock. Inside Marcus Munitions. Near Claptrap's location, at the end of the street and in front of a building. Inside Scooter's garage, near a stack of tires under the stairs. Inside Crimson Raider headquarters in the room with Tannis. Inside Zed's clinic. To the left of the door to Crazy Earl's Black Market.
Notes. In the unpatched console versions, Michael has a 100% spawn chance before Sanctuary is relocated, after which point his spawn rates returns to the default 10%.
As requested by u/gavyn377 here's a list of all the legendary weapons in roughly story mission order. Where you get to access a location like The Dust I've listed all the weapons that appear there and the level/mission you have to be on to gain access to it! If you like this game, buy it here Borderlands 2 2K Games Gearbox Software Action Release: Sep 18, 2012 (US) ESRB: M Borderlan.
In the PC version, he always has the normal 10% spawn chance. Based on performed by user DarkForce9999 in Gearbox Forums, his ratio appears to be 95% blue, 4.5% purple and 0.5% orange. Based on a performed by user Heycarnut posted at Gearbox forums, the ratios were 89% blue, 11% purple, 0% orange. Assuming the 0.5% orange rate inferred from an earlier test by another poster, there is only about 0.6% chance of not seeing an orange in this many drops, strongly indicating the rate may be much lower.
He will occasionally paraphrase a version of the opening theme from if left alone for a while before his offered item is taken.