Lopez's Relationships

Lopez's relationships with the other characters seems to be on rough terms. Interestingly, while Lopez hates the other members of the Blood Gulch Red and Blue teams, he still seems to care about them to the point where he'll save them. One point is when he calls Lopez 2.0 an 'annoying moron', implying that although he hates the others, he won't go to extremes like Lopez 2.0 did and try to kill them.

Red Team
As time passes, Lopez realizes that all of the Reds are fools and has developed rough relationships with them.

Sarge
Due to the fact Sarge built and programmed him personally, Lopez initially loved him but grew to dislike him later on due to his insane plans and absurd ideas. Usually, he claims he would prefer to die than listen to him and during Reconstruction when Sarge contemplated leaving, Lopez begged him to go (though Sarge thought he was asking him to stay). Sarge eventually leaves and Lopez initially rejoices. Afterwards, he receives a call from Sarge asking him to come to Valhalla and help him build a Holographic Projection room. Lopez was reluctant at first but eventually went to help.

Simmons
Lopez dislikes Simmons' attitude, seeing him as racist and as much of an idiot as the rest of the team. Despite this, he is still willing to build machines for him and lends support during the confrontation with the Meta, including saving his life. Simmons also was able to relate with Lopez by explaining he is part cyborg and shows to have a mild understanding of Lopez. In conclusion, Lopez seems to have the most friendly relationship with Simmons of all the other members of the Red team.

Grif
Lopez hates Grif simply because Sarge programmed him to. When Sarge orders him to execute Grif, Lopez is extremely grateful and happily complies. Considering Grif's nature, it is likely that Lopez hates him naturally as well.

Donut
Of all the members on the Red Team, Donut is perhaps the one Lopez hates the most. Like Simmons and Grif, he finds Donut highly annoying due to his idiotic mood and his terrible attempts at translating Spanish. In Recreation, after the Meta attacked, when Donut appeared in Red base, Lopez suggested to Simmons to kill Donut "in case" he was the Meta in disguise, but if not, Lopez still suggested they kill him nonetheless.

Lopez 2.0
Lopez seems to get along very well with his successor, even referring to him as "kid" at one point. He also tells Lopez 2.0 all about his history with the Reds and teaches him to ignore orders and insult Sarge in Spanish, much to the latter's enjoyment. Lopez initially wanted himself and Lopez 2.0 to join forces against the teams, but the latter betrays him. After Lopez 2.0's death, Lopez takes the latter's body and refers to him as an "annoying moron".

Blue Team
During his time on Blue team, Lopez seemed to tolerate the Blues. However, he later considers them being as foolish as the Red team.

Tucker
Lopez and Tucker seem to be able to work together on decent terms, mainly when they and Sheila work together to get the Red Team to turn off their headset radios. When Lopez and Sheila revealed they were leaving the team, Tucker couldn't believe it. It's also shown that Tucker is one of the few characters that understands him. In Season 11, Lopez saves Tucker from a Federal Army soldier, and when he is shot, tucker displays extreme concern for him.

Church
Lopez has little interaction with Church, but he shows to dislike him due to being "constantly possessed and blown up", which eventually caused him and Sheila to create their own army, which was because Future-Church gave them the idea.

Caboose
Caboose is Lopez's rival for Shelia's heart and dislikes him for it, but Lopez shows no contempt for Caboose for this reason.

Sheila
When Lopez and Shelia first met, they instantly fell in love, having a brief, affectionate talk before Lopez is shooed off by Caboose. Afterward, Lopez sings a love song for her when making the Red's turn off their headset radio and they soon developed their own army. After O'Malley/Doc kidnapped him, Lopez and Sheila have had little to no interaction with each other, but he's shown to still be in love with her when seeing her in Why Were We Here?

Sister
After Sarge leaves Blood Gulch, Lopez apparently killed Sister and tells Sarge of their victory. It should be noted that Sister was one of the few characters that could understand him.

Washington
Lopez has no interaction with Wash apart from being shot by him.

Meta
Lopez has no direct interaction with the Meta apart from detecting him as an immense danger, and shooting him with a Missile Pod. He, along with Simmons and Donut, defends the Red Base from him before trying to escape.

Omega
Despite being kidnapped by O'Malley, Lopez accepts any order given by him and manages to work with him, as he defends Zanzibar from the Reds and Blues and even builds him a robot army. However, Lopez's relationship is more strained with O'Malley than with Doc, as Lopez does insult him, trick him to insult himself, and corrects his spelling mistakes from time to time.

Doc
After Lopez is kidnapped by Doc/O'Malley, he becomes their minion in the mission to destroy the Reds and Blues and take over the universe. His relationship with Doc seems decent and friendly when compared to Omega's. Doc seems to understand Lopez, he agrees with Doc more than O'Malley, and it's suggested that Doc got a g-mail invite from him. However, Lopez is later shown to be angry at Doc for forgetting about him during Season 5.