Sweet Mask/Relationships

Genos
Sweet Mask has a generally low opinion of Genos. He converses with Genos after the latter is admitted directly into the S-Class without Sweet Mask's approval, a fact that bothered him, but after seeing that the cyborg seemingly matches up with his view of heroes, he accepted it nonetheless. He speaks to Genos a second time after the Dark Matter Thieves are defeated, calling Genos a "disappointment" (referencing his defeat by the Deep Sea King and his inability to assist against the alien threat). However, Genos does not seem to be bothered by his comments and noticed the similarities between Sweet Mask and him before he met Saitama.

King
Sweet Mask respects King for what he claims as "actually pulling his weight as an S-Class hero." Sweet Mask felt strongly enough about it to stop arguing with Flashy Flash when King entered the room.

Flashy Flash
Sweet Mask easily antagonizes Flashy Flash, almost to the point of clashing. As with most of the other S-Class heroes, Sweet Mask believes himself superior to Flashy Flash.

Flashy Flash does not like Sweet Mask's authoritative and egotistical attitude. While he has some disdain towards some of the S-Class heroes, the tone he gives off is either of annoyance or even teasing, as seen with his interactions with Metal Bat. Flash's displeasure towards Sweet Mask goes to the point of eliciting his murderous intent towards the fellow hero. He goes out of his way to instigate a challenge against Sweet Mask.

Zombieman
Sweet Mask mockingly (but accurately) calls Zombieman a monster, calling into question his inhuman regeneration abilities and mysterious past. Zombieman is annoyed by Mask, but maintains his cool. Sweet Mask's view of Zombieman changes later on during the Monster Association raid, calling him a pseudo monster instead of an actual monster. However he still sees Zombieman as a pseudo monster nonetheless as opposed to his view of an ideal human able to lead a team of heroes, but he becomes calmed and wistful by Zombieman's words about them being all humans, and is shocked when Zombieman is hit by Homeless Emperor's attacks.

Feather
While he looks down on most heroes, he respects Feather, saying he has star potential.

Blast
Not much is known about their relationship with one an another, but as seen from his flashback, Blast saved him from a unknown monster. The respect and admiration he has for Blast gave him the strength to control himself once more.

Superalloy Darkshine
When Darkshine resurfaced after being defeated Garou, Sweet Mask was angry seeing Darkshine in the mental state he was in, going as far as to kick the hero hard multiple times, likely due to the reflection of how Sweet Mask himself had panicked and nearly lost his composure multiple times during the raid. Despite this, as Puri-Puri Prisoner attempts to consolidate Darkshine, Sweet Mask gives him his own support, stating how they're both the same and need to push forward despite setbacks they face. In the end, Sweet Mask showed that he has respect for Darkshine as well, acknowledging his muscles as a sign of overcoming himself and encouraging him to stand up and keep moving forward, and was proud to see Darkshine get up and keep going.

Saitama
When first hearing mention of him after Saitama killed the Sea King, Mr. Mask's opinion relegates the newbie as having the aura of a B-Class hero, based on appearances via the video feed alone. After watching the footage of Saitama defeating Sea King, Sweet Mask begin to have a minor interest in the caped bald hero's tremendous strength, thus allowing to rank Saitama up to B-class.

After witnessing Saitama defeat Garou, however, not only does Sweet Mask fully acknowledge Saitama's tremendous strength but becomes somewhat obsessed with him, considering him to possess the true beauty of overwhelming power, which meets his standards of being a hero. He would start comparing new heroes with Saitama, even starting a new hero project that would feature the bald hero. Despite his admiration for Saitama, he still showed great displeasure for his refusal to kill Garou and lectured the hero for it.

After Sweet Mask told Saitama his origins, Saitama told him that appearances and origins don't matter, nor does the public opinion and that how you view yourself is more important. When a monster known as Pesky Clown attacks the citizens and fights Sweet Mask singlehandedly, the monster becomes too powerful for Sweet Mask to fight in his human form and he was forced to transform into his monster state. After realizing its meaning, Sweet Mask finally takes Saitama’s advice to heart and sacrifices his handsome appearance to defeat the monster and restart his new heroic life.