Abilities
Lily is a genetically modified human capable of regenerating her cells from most injuries in a matter of minutes. Furthermore, the modifications make her super-strong and ultra-fast, allowing her to potentially take down a man three times her size without him having a chance to fight back.
Due to her training with Bishop, she's also fairly good with handguns and other assorted firearms.
Strengths
Loyalty - Once you're ingrained into her memory as a friend, she considers you her friend for life.
Healing factor - Lily is capable of healing from any injury near-instantaneously. Unless the brain itself is actually destroyed, it is impossible for her to die from a physical injury.
Heightened Senses - Lily's senses are three times as good as a human. At least, her senses of smell and hearing are. With eyesight, it's mostly that she's better able to pay attention to details than most people.
Intelligence - Despite her memory problems and naivety due to this, Lily is also a fairly intelligent girl. Even in her berserker state, she's more prone to strategy than to outright force when necessary and can usually piece together how things are "supposed" to be from sufficient enough evidence.
Crafts - Lily likes to work with her hands. As such, she's gotten quite skilled at various practical crafts, such as cooking, sewing, woodworking, pottery, and other various things. Granted, she by far isn't the best at them, but she does love making them and is fairly practical with them.
Weaknesses
Exhaustion - The berserker state she goes into ultimately forces her into a state of fight-or-flight she has no control over. If left in this state too long, it takes its toll on her body.
Heine - Lily's greatest weak point is her brother, Heine. The two of them helped and protected one another Underground and refuse to be anywhere without one another for long stretches of time. She is prone to worry about him if he's out of her sight for more than an hour as he has a tendency to brood while Lily wants to simply forget.
Nightmares - Due to her trauma in the Underground and the tampering with her brain, Lily sometimes suffers from recurring nightmares of the things her Dog did to the other children and the various other experiments she was forced to undergo.
Memory - Lily has a bad memory. Most often, when a person is genetically modified to gain something, they lose something else in return. In Lily's case, she lost a good chunk of her long-term memory. Nothing stays too clearly in her head unless she's drilled it into a routine and has to use mnemonic devices to remember names and faces. If something out of her normal routine has occurred and more than a day has passed, she will forget it completely. Similarly, if something occurs regularly over the space of a month, she will be able to remember it.
Naivety - Lily was raised in an Underground research facility, followed by a church, and then has a very bad memory. She isn't wise to manipulation or the ways of the world at large. Heine mostly stayed around her to make sure she wasn't manipulated into doing stupid things as her fractured memory makes her especially vulnerable to being used since all someone really has to do is convince her she promised to do something a few days before and she'd believe them.