Uncle Leo

Uncle Leo is a friendly, wandering super mutant, easily identified by his lack of armor (wearing only a pair of shorts) and the fact he displays as your set HUD color (friendly) on the HUD. He is an exile of sorts from the super mutants; he ran away before he could be killed, because he was showing peace/dissent among his kind. Since then, he has roamed the Capital Wasteland and can be encountered in a random encounter. He frequently refers to the Lone Wanderer as either "Little Brother" or "Little Sister", depending on the PC's gender.

Uncle Leo is non aggressive, and will never initiate combat (even against Yao Guai or Deathclaws), but will defend himself if attacked. He also attacks any enemies that attack the player character. However, he has only moderate morale, and will drop his weapon and run away if he takes too much damage.

He is initially unarmed, but like all NPCs will try to acquire weapons from the environment if brought into combat. His health is on par with that of a Super Mutant Master, so he's fairly capable of handling any random enemies the Capital Wasteland throws his way while he's wandering around. However, at higher levels, he does run the risk of getting killed by randomly spawning Mr. Gutsys, Sentry Bots, or Deathclaws. He also cannot heal damage or be given/reverse-pickpocketed stimpacks, so repeated enemy encounters will eventually mean the death of him.

Location
Uncle Leo is a random encounter, and might be found in any of those locations.

Interaction
When speaking to Uncle Leo, he will be surprised that you haven't shot at him yet. As long as you're nice to him, you can get more than information. When the option comes in at the top to tell him to give you his goods (essentially robbing him), he gladly imparts a suit of Dirty Pre-War Businesswear (possibly intact) to you as a gift, wishing he could give more.

Asking him what he meant when he said "before I became this" causes him to tell the player that Super Mutants are not born, but are made by other Super Mutants in a cold, dark place. He mentions that they use the captives that they take to make more of themselves, but either doesn't know or cannot explain how this is done. Depending on when he shows up and how the player chooses to explore, this could be the game's first reference not only to what Super Mutants do with their captives, but how they come into being.

Attacking Uncle Leo causes him to switch to hostile. However, once the game finishes running the attack animation, Uncle Leo returns to friendly, even when the player is obviously his tormentor. Attacking and/or killing him causes no change in karma.

You can lure any nearby enemies towards Uncle Leo, who will attack them for you. This is especially helpful for swarms of Mirelurks or Super Mutant Masters.

Given the canonical method of Super Mutant creation, this may be an indication that The Master's experiments are being continued, perhaps without true understanding of why, by the surviving Super Mutants. This would also imply that there is another FEV vat located somewhere in the DC Wasteland to which they take captives in order to be dipped and transformed, though in the vault they are supposed to come from they seem to be infected by way of a gas chamber rather than being dipped in a vat. The player may also overhear Super Mutants chatting about finding more "green stuff", as they are running low which is indicated when you try to activate the infecting rooms in vault 87. If you need further proof that Vault 87 is the breeding ground for the Super Mutants, you can talk to Elder Lyons after you escape Raven Rock, and a dialogue option will appear stating that it is the breeding ground.

Uncle Leo can be encountered at least two times around the Capital Wasteland; at the second time you meet him he will tell you how after your first encounter with him he fell into a dark cave while climbing a hill and hurt his leg. The cave turned out to be an old basement in which there was stacks of purified water. He tells you that after he got out of the basement he has been hunted by a group of "bleeders" (as super mutants refer to humans) and that he was forced to abandon the water he was carrying. Like during the first encounter, he will offer you another suit of Dirty Pre-War Businesswear, wishing he could give you more.

Appearances
Uncle Leo appears only in Fallout 3.

Behind the scenes

 * Uncle Leo's dialogue when you try to rob him, where he tells you the clothes are a gift and he wishes he could give you the "wonderful moon" comes from the following Zen Buddhist koan:

''Ryokan, a Zen master, lived the simplest kind of life in a little hut at the foot of a mountain. One evening a thief visited the hut only to discover there was nothing to steal.  Ryokan returned and caught him. “You have come a long way to visit me,” he told the prowler, “and you should not return empty-handed. Please take my clothes as a gift.”  The thief was bewildered. He took the clothes and slunk away.'' ''Ryoken sat naked, watching the moon. “Poor fellow,” he mused, “I wish I could have given him this beautiful moon.”''


 * Together with the Zen philosophy from Fawkes, this suggests that Zen Buddhism is a means to retaining some level of independent mental function after FEV transformation. This is further suggested by Fawkes quote about 'how the pain causes them to lose their humanity', as Buddhisms teachings are based on conquering pain.
 * Uncle Leo may be reference to Elder Scrolls IV: Oblivion, because there is a friendly zombie with the same name living upstairs of Muurine's house in Crucible, New Sheoth in the expansion Shivering Isles. Uncle Leo has no dialogue and simply walks around the room.