Leslie

Leslie is the first major character that the protagonist encounters in Colleentale. Leslie serves as the main antagonist for the majority of the movie, specifically the Neutral and True Pacifist routes, and can be considered a deuteragonist for the Genocide Route. He provides an introduction to the mechanics of encounters by sharing "friendliness seeds," which are actually harmful bullets, revealing his philosophy of "KILL or BE KILLED."

Appearance
Leslie has the appearance of a conscious pink daisy. His structure has a yellow androecium, eight yellow petals, and a light-green stem. Leslie can contort his face to show various expressions and can mimic the faces and voices of other characters. He mimics Fluttershy and Asgore Dreemurr in some situations, as well as his old self at the end of the Genocide Route. He also mimics the protagonist's face before the Neutral Route's final battle.

Personality
Initially, Leslie operates under a facade of friendliness and politeness. He often greets the protagonist with southern slang, such as "Howdy!", calls himself "your best friend," and, like his father, appends polite words such as "gosh" and "golly" to the ends of his sentences. Whenever he drops this guise of friendliness, he often calls the protagonist an "idiot."

Leslie has a malevolent and cruel disposition, berating the protagonist for not following his "kill or be killed" philosophy. Despite this, he also criticizes the protagonist at the end of the Ruins if she killed any monster. He is manipulative, devious, and a cunning planner and subtle if the circumstances require it. He retains his memories between SAVEs because he was once able to SAVE. He is also shown to be extremely cowardly, as he kills his former father to appease the protagonist in a vain attempt to save his own life in the Genocide Route's conclusion.

Main Story
Leslie introduces the concept of the space and calls his bullets "friendliness seeds."
 * If the protagonist dodges three times, his friendly act slips and he hypocritically snaps at the protagonist for leeching off of him.

When the protagonist runs into his bullets, he announces his central philosophy. Regardless of whether the protagonist dodged Leslie's bullets or not, he then attempts to kill the protagonist with an unavoidable ring of bullets, but Fluttershy intervenes and saves the protagonist.
 * The background music lowers by one semitone each time the bullets are dodged, before slowing, lowering pitch, and stopping entirely.
 * Before his third attack, Leslie questions the protagonist's mental capacity, before bellowing in frustration "RUN. INTO. THE. BULLETS!!!" before quickly looking directly at his script and changing the "BULLETS!!!" in the word to "friendliness seeds."

If the protagonist killed Leslie on a previous Neutral Route, he does not appear. If the protagonist spared him, he reminds the protagonist not to kill anyone. If the protagonist gained no EXP, he reminds her to befriend everyone. After resetting a Neutral Route multiple times and repeating Leslie's initial encounter, he becomes annoyed and questions if "you have anything better to do."

If the protagonist resets a Genocide run before or after killing Dragonizer the Dragon, Leslie says "Really, Chara? Well, do what you will. I'll be waiting for you!" before leaving.

Ruins End
At the exit to the Ruins, Leslie judges the protagonist's actions up to that point. Leslie does not appear to judge the protagonist if he was killed in a previous Neutral Route.

Neutral Route
After the Ruins, Leslie will be seemingly absent until the end of Asgore's battle. However, backtracking in some rooms allows the protagonist see Leslie burrowing back into the ground on the edge of the screen.

Leslie also leaves a message on an Echo Flower in the vertical room before the bridge in Waterfall that changes if the protagonist spared or killed Fluttershy.

If the protagonist decides to kill Asgore, Leslie appears, destroys Asgore's SOUL, and absorbs the six bottled human SOULs. If the protagonist spares Asgore, Leslie appears and kills Asgore himself. Then, the movie goes to the next part and Flowey's battle begins after going to the next part.

After he is defeated, the protagonist has the chance to spare or kill Flowey. Flowey requires the protagonist to offer him mercy multiple times before he flees, unsure why the protagonist is being nice to him.

If the protagonist loads or finishes another Neutral Route, Leslie does not absorb the SOULs because he knows that they would rebel again. Instead, the protagonist will be able to exit the room and receive Dragon's Neutral Route phone call.

If spared after his battle, Leslie advises the protagonist during subsequent Neutral Routes. If the protagonist gained EXP before his battle, he asks the protagonist to prove his philosophy wrong, as he thinks it may be meaningless. Leslie also offers unique dialogue if the protagonist only killed Asgore and tells the protagonist that she wasted everyone's time. If the protagonist earned no EXP, yet she has not met all the requirements for the True Pacifist Route, he mentions that the protagonist should get closer to one of the main characters, depending on who she previously befriended.

The protagonist can then recover her previous SAVE file and follow his advice.

If the protagonist kills Leslie, he recognizes that the protagonist can kill before becoming "just a regular daisy."

If he was killed after his battle, Leslie does not leave a message for the protagonist after the credits close, and, after a reset, does not appear until after the resolution of Asgore's battle. Leslie then berates the protagonist for thinking that killing him solved anything. He explains that he was brought back when the protagonist loaded she SAVE file and that she still cannot achieve her happy ending.

If the protagonist nearly completes a Genocide Route but resets after killing Amy Rose the Hornhog, Leslie becomes upset with the protagonist. However, he then proclaims that the protagonist just wanted to see everything in the Underground and will eventually return to her malicious ways.

True Pacifist Route
For further information, see Shadow the Hedgehog.

Genocide Route
For further information, see Shadow the Hedgehog.

In Battle
As a daisy, Leslie uses only three attacks: a five-bullet spread that slightly hone in on the protagonist's SOUL, a large ring of bullets which surround the SOUL and cannot be dodged and a vertical row of bullets which come from the side of the space, from outside it. This attack is only used before his battle as Super Shadow. He can speed up the spread although the limits of his attacks and speed are unknown. Getting hit by his five-bullet spread in his first encounter deals 19 damage per bullet whereas the unavoidable ring attack heals 19 HP regardless of whether it hits the protagonist. Before his battle as Super Shadow, the bullets deal 7 damage until 6 HP where it is 5.

Relationships
For further information, see Shadow the Hedgehog.

Trivia

 * Leslie was originally going to be a vulture version of Flowey, this was changed due to some characters talking about him, Leslie.