|This article is about a/an episode in Kamen Rider Drive.|
Who Loves Heart the Most? (だれかハートを一番愛したのか Dare ka Hāto wo Ichiban Aishita no ka) is the forty-fourth episode of Kamen Rider Drive. It features the debut and only television appearance of Jun Honganji as a Mass Production Model Mach aka "Kamen Rider Jun"  This also marks the final appearance of Brain.
Brain was cornered by Gold Drive and Roidmude 004, who wished to trigger a second Global Freeze. However, he was saved by Drive. Drive helps Brain escape but Kiriko is wounded in battle. Now aware of his own feelings for her, he feels very troubled while rescuing her. Meanwhile, Brain was looking into Medic’s sudden change after escaping. When he reached the fragment of his claw in Medic’s body and finds out the truth behind the change in her system, he also discovers that his very existence, along with Heart’s and Medic’s, is in terrible danger.
Drive escorts Kiriko to safety, while Mach and Chaser fight 004 and Gold Drive before the latter flee. Brain uses the stolen tablet to link into Medic's system and finds a shocking truth about her programming. She appears behind him with three Reapers but instead of running, Brain surrenders.
Kiriko was hospitalized after the event and while Chase and Go tries to take a visit, they see Shinnosuke at the front door of Kiriko's ward bringing some gifts and orders Chase to give them to Kiriko, much to Go and Mr. Belt's surprise. In the SSDC headquarters, news of all four Over Evolved Roidmudes had reached the Special Investigation Unit and Akio. With the second Global Freeze may affect worldwide, Rinna introduces Pikopiko 4, a lighter version of Pikopiko 3 with five having been created so far. Rinna introduces the Mach Driver Production Model and its wearer Jun, as he demonstrated it and transforms into the first production model of Kamen Rider Mach, aka. Kamen Rider Jun. But an error occurs which renders the suit suddenly immobile, and Akio gives them some more time to finish the suit.
Chase visits Kiriko and asks her if she harbors feelings for Shinnosuke, which she denies. Chase however, believes that she lied much like Shinnosuke, and sheds tears but willingly holds the burden as it makes him feel closer to be a human. Soon, several places had been declared a state of emergency and the police forces, including Special Investigation Unit are searching for the Promised Land. Meanwhile, Rinna and Kyu had stay all night to mass produce the Pikopiko 4 as quickly as possible. Heart chastises Brain for surrendering to Banno. Gold Drive reveals 004's creation, Sigma Circular and orders the party to head to the Promised Land. Brain adopts his true Roidmude persona and throws away his handkerchief as a first step of shedding his humanity.
At the supposed location of the Promised Land (a lakeside), a group of Roidmudes appear for the ceremony of the Promised Numbers, as police officers hide for guerrilla attacks. The Kamen Riders arrive late and Genpachiro reveals that the location was leaked by "Mr. X" but Go denies to having using that nickname again. The Kamen Riders act first to attack the ceremony but Plain Roidmude and Reaper Legions block their way. With the Over Evolved Roidmudes exhausted, Genpachiro and the special forces try to aid the Riders but the Sigma Circular activates and reveals its true purpose: to absorb and recreate the energies of Over Evolved Roidmudes for the creation of Global Freeze. But to stabilize its excess power, one must become a sacrifice to it and that person is Medic, whom Banno brainwashed with the trojan program and modified with a targeting program to direct the energy to her body. Her death would also ensure that no means of healing for Roidmudes would exist, so if the Roidmudes begin to rebel, Gold Drive could easily slaughter them all as punishment. Seeing Heart loves her more than anyone, Brain relocates the target program from her body to himself, at the same time saving her from Gold Drive's trance.
Eventually, Brain's largest gambit proves fatal, releasing a huge explosion and in his final moments wishes Medic to take care of Heart before rusting away into nothingness and his core disintegrates. Tired of his devilish acts, the Riders attack but once again are occupied by their enemies until they finish them with Full Throttles. With Banno surrounded by the Kamen Riders and Roidmude Executives, 004 surprisingly survives and reveals that this place is not the Promised Land but rather a place for the ritual. Banno laughs insanely and confirms this and reveals that he was the one that lured all of them here under the name Mr. X. He traps them all in an electromagnetic field and 004 commits a kamikaze attack via self destruct so Gold Drive can escape, seemingly killing all of them in one blow as Banno plots the end of the world with the Global Freeze.
- Shinnosuke Tomari (泊 進ノ介 Tomari Shinnosuke): Ryoma Takeuchi (竹内 涼真 Takeuchi Ryōma)
- Kiriko Shijima (詩島 霧子 Shijima Kiriko): Rio Uchida (内田 理央 Uchida Rio)
- Chase (チェイス Cheisu): Taiko Katono (上遠野 太洸 Kotono Taiko)
- Go Shijima (詩島 剛 Shijima Gō): Yuu Inaba (稲葉 友 Inaba Yuu)
- Drive Driver's voice (ドライブドライバーの声 Doraibu Doraibā no koe), Roidmude 004 (ロイミュード００４ Roimyūdo Nanbā Zero Zero Yon, Voice), Narration (ナレーション Narēshon): Chris Peppler (クリス・ペプラー Kurisu Pepurā)
- Jun Honganji (本願寺 純 Honganji Jun): Tsurutaro Kataoka (片岡 鶴太郎 Kataoka Tsurutarō)
- Rinna Sawagami (沢神 りんな Sawagami Rinna): Rei Yoshii (吉井 怜 Yoshii Rei)
- Kyu Saijo (西城 究 Saijō Kyū): Kenta Hamano (浜野 謙太 Hamano Kenta)
- Genpachiro Otta (追田 現八郎 Otta Genpachirō): Taira Imata (井俣 太良 Imata Taira)
- Brain (ブレン Buren): Shota Matsushima (松島 庄汰 Matsushima Shōta)
- Heart (ハート Hāto): Tomoya Warabino (蕨野 友也 Warabino Tomoya)
- Medic (メディック Medikku): Fumika Baba (馬場ふみか Baba Fumika)
- Tenjuro Banno (蛮野 天十郎 Banno Tenjūrō, Voice): Masakazu Morita (森田 成一 Morita Masakazu)
Shift Cars & Signal Bikes
- Car Used:
- Type Change: Shift Wild, Shift Tridoron
- Tire Exchange: N/A
- Type Used:
- Type Wild, Type Tridoron
- Type Change: Shift Deadheat
- Tire Exchange: N/A
- Form Used:
- Deadheat Mach
- Tire Blending used in Type Tridoron:
- Attack 1.2.3
- Bike Used:
- Form Change: Signal Mach, Shift Deadheat
- Signal Exchange: N/A
- Form Used:
- Mach, Deadheat Mach
- Form Change: Signal Chaser
- Form Used:
- Form Change: Tokujo-ka Key
- Form Used:
- Mach (Production Model)
- When Drive Type Tridoron is about to finish off 004, the Drive Driver announces "Hissatsu! Flare Spike Shadow!" before Drive assumes Type Tridoron Attack 1.2.3 with the belt announcing "Tire Kakimazerl: Attack 1.2.3!", without saying "Full Throttle!". This is something that the DX Shift Tridoron cannot do (unleashing a finisher during the Tire Blending).
- When Deadheat Mach is about to finish off a trio of non-Reaper Legion Roidmudes, the Mach Driver Honoh announces "Hissatsu! Full Throttle!" before Mach spins the front wheel of the Zenrin Shooter for a Hit Macher, completely omitting the "Burst" and "Dead Heat" parts of the announcement.
- Their Cores were also misplaced upon the destruction of their bodies, with 107 being the Cobra and 073 being the Bat.
- As part of Super Hero Time, this episode aired alongside Shuriken Sentai Ninninger episode 27, Shinobi 27: It's Summer! Chozetsu Star is Born!.
- Viewership: 4.6%
- Closing Screen Shift Car/Signal Bike
- Roidmude Count
- Answer to the episode's question: Brain, as he is willing to sacrifice himself to save Medic for Heart's sake.
- As of this episode, with the deaths of 021 and 097, all Roidmudes who have Core numbers in the 20s and 90s range are eliminated.
- Most of the active Kamen Rider mobile games provided relevant projects to commemorate Brain's death following this episode's broadcast. Such as Kamen Rider Break Joker, Kamen Rider Storm Heroes, Kamen Rider Megaton Smash, and Kamen Rider Riderbout.
- Final appearance of Drive Type Wild and Type Tridoron Attack 1.2.3.
- It also marks the return of Drive's Type Tridoron Attack 1.2.3 form since episode 37.
- This is the only time Jun Honganji utilizes the Tokujo-ja Key to transform into Kamen Rider Jun.
- Upon transformation, Honganji is screaming "Toh!", a prominent battle cry of most Showa era tokusatsu series like the original Kamen Rider, Himitsu Sentai Gorenger, and many more.
- Coincidentally, Honganji's first transformation rendering him immobilized is also similar to Doctor Ulshade's first transformation into Kyoryu Violet in his debut episode in Zyuden Sentai Kyoryuger. Riku Sanjo is previously the main writer for Kyoryuger, and currently the main writer for Drive.
- This episode marks the greatest number of Roidmude casualties with a total of 8, beating episode 41's record of 7.
Kamen Rider Drive Volume 11 features episode 41-44: How is the Golden Drive Born?, Where is the Truth About the Goddess?, When Will the Second Global Freeze Start? and Who Loves Heart the Most? 
Collection 4 comes with 12 episodes.