Elise/Synopsis

Armed Detective Agency vs. Port Mafia Arc
Elise first appears during Mori and Higuchi's meeting after Akutagawa's defeat against Atsushi. Elise is seen drawing on the floor later showing it as a drawing of Akutagawa decapitated. Elise then goes up to the table and absently listens to their conversation, smiling and seeming disinterested, even yawning despite the weight of the situation. She doesn't say a word, merely watching Higuchi with noted amusement.

The Guild Arc
Although largely absent during the events, Elise goes "missing" just a bit before Lucy captures Mori, Atsushi, and Tanizaki. Mori approaches Atsushi, asking if he's seen his daughter, which he hasn't. After Lucy's defeat, Elise approaches Mori herself, happily telling him she intentionally went missing to make him cry. Elise and Mori walk down an alley together, where Mori says he wishes he was younger and could defeat his foes with ease. With a taunting smile, Elise calls him "Mr Midlife Crisis". Soon after their light-hearted banter, the two approach the grisly scene of prominent Port Mafia mafiosi surrounding a corpse, an assassin from the Guild.

Later on after the Guild attacks both Port Mafia and Armed Detective Agency members, the latter taking Kōyō under their watch, Elise is seen eating a plethora of desserts without a care in the world. Mori attempts to curb her appetite, but Elise refuses, calling sweetness "true justice". She's quick to manipulate Mori by telling him she'll try on one of the many dresses he bought her if he lets her eat to her heart's content. She continues her feast, unfazed by Mori's seemingly drastic decision to kill Yukichi Fukuzawa. Chūya Nakahara laters informs Mori the assassination attempt failed, as Mori expected. Off to the side, Elise reads by herself in Mori's office chair, wearing the dress as promised.

Elise later plays around, drawing on the floor with crayons and humming to herself. Her carefree antics add to Mori's disturbing excitement in strategising a counterattack against the Guild, which Elise calls lame. Mori suddenly takes one of her crayons, angering Elise. The whole time Mori writes a letter addressed to the Guild's Margaret Mitchell and Nathaniel Hawthorne, Elise yells at Mori to give her crayon back and take her outside to play. As the battle rages on, Mori plays chess by himself, and Elise amuses herself by drawing on the office walls.

Afterwards, Elise remains largely inactive, absent when Mori faces Fukuzawa to arrange the ceasefire and the victory party between Mori, Chūya, and Kōyō.

DEAD APPLE
As Mori's ability, Elise is affected by Shibusawa's fog, going berserk in attempts to kill Mori. She's shown easily overpowering him, as he can't bring himself to harm her. However, she meets her defeat against Fukuzawa after the two switch battles. After turning back to normal, she yells at Mori for trying to "leave her behind".

Cannibalism Arc
During an excessive shopping trip with Mori, Elise snaps, asking why they haven't reached a dessert shop yet. To her chagrin, Mori tries to get her to go to a tailor's shop - the fifteenth one of the day. Mori tries convincing her to play along, saying he might die seeing her in something new, and Elise encourages him to die whenever he's ready. She storms off to their car, which explodes the second they get in. Mori activates Elise as Vita Sexualis, and she grabs him by the collar, flying him over the explosion, both unharmed, and her strength increased so much she ripped the door off when flying away. Despite being safe, Elise feels nothing but contempt for saving Mori, dropping him without hesitation when he comments his neck hurts. She dismisses his gratitude, unhappy about saving him since, as his ability, she's forced to upon his whim. Mori tries to calm her, but she points out she hates the arrangement as he's always the one that gets to "set the scene".

With a crowd gathering at the explosion, both attempt to leave going unnoticed, however, a police officer stops to check on them. Trying to deescalate the situation, Mori lies and claims Elise poured orange juice into the gas tank because the "car seemed thirsty". This only angers Elise, feeling she's being made a fool of. Mori assures the officer they're both fine, and the officer suddenly stabs him in the abdomen. His police hat falls off, revealing Fyodor Dostoevsky. Mori orders Elise to pursue him, and her speed and flight increase, but she loses sight of him in the crowd. Infected by Alexander Pushkin's virus, Mori becomes too weak to keep Elise around and she disappears.

Once the Cannibalism operation forces the Port Mafia and Agency to try and kill each others' leaders, Mori leaves the mafia's protection to face Fukuzawa one-on-one and minimise the damage their organisations suffer. Although weak, he's capable of summoning Elise for combat. In this stage, Elise arrives in a nurse's dress, armed with a giant syringe to fight. She and Fukuzawa engage in a fierce battle, however, Fukuzawa defeats her and cuts her body into many pieces. Soon just a floating head and detached arms, Elise apologises to Mori, promising to see him next time before disappearing. She is not seen again until after Pushkin's defeat, alongside the rest of the Port Mafia and Agency.