Jaqueline is someone Kirk considers a kindred spirit, someone he can relate to: they both have a passion for science, and both have used it to become something more than human. Kirk greatly appreciates Jaqueline's intelligence, and the two are often seen talking about complex science stuff.
She is also the only girl Kirk is not shy around.
It is hinted numerous times that Kirk feels more than friendship towards Jaqueline. However, he is fully aware of her passion for Mikey, and, since he respects her so much, has not pursued his feelings. That does not stop him from being sad every time she embraces the wolf boy.
Kirk considers Jackie a force of nature, unbound by society and its laws. He greatly respects her strength, and is often seen sparing with her during training sessions. In the midst of battle, the two are very coordinated.
Tough Jackie constantly flirts with him and often gets MUCH closer than necessary, Kirk doesn't seem to mind. He will still blush heavily when she does so, and will attempt to punch her back, but he doesn't seem to insistent.
It is hinted that Kirk has feelings for Jackie as well. This has led some to ask themselves which of the two girls Kirk actually likes, and which he likes because of the shared body. However, given Kirk's personality, he most likely sincerely cares for both of them, despite their sometimes conflicting personalities.
Kirk has grate respect for Vincent, and will follow his orders without question. Most of the time, he refers to Vincent as "Commander", thus showcasing his respect.
Kirk has a grate friendship with Suu, the two actually getting along very well... though this is partially due to the fact that she is the only one that doesn't mind donating samples of herself for Kirk to study.
In Kirk's opinion, Zack is nothing more than a self absorbed, arrogant, immature, big mouthed, ... caring, compassionate and gentle, yet chaotic hero. Though the two often argue (with Zack commenting on Kirk's "old man language"), Kirk cares a lot for the zombie, and he will not hesitate to put himself in harms way to help him.
Kirk likes spending time the Cyclops, and enjoys her company. He finds her very interesting (mostly due to her having one eye). He is very curios to why she has two eyebrows, despite having only one eye. This has lead him to sometimes asking for biological samples from Irene, the way he asks kind of scares her.
Kirk gets along with Dru very well, and he is one of the only persons who can understand what he is saying. The two often talk about animals, since they both like them very much.
Kirk is very interested in studying Dru's genetic makeup, especially his regenerative factor. He has stated that it may be possible for him to synthetize a Regen serum from Dru's blood, though he has no answer to how to create it.
Kirk is somewhat intimidated by her appearance, even though he knows of her gentle nature. Besides that, the two go along very well.
He will sometimes give her the title of "gentle giant".
The two get along pretty well, with Kirk being able to relate with her due to their conditions.
Kirk also dislikes her short temper and her rushed actions, and will often scold her for her recklessness.
Though Kirk has no animosity towards her, he could do without the 5Km run. Polly has also developed a special series of exercises, designed to help the muscles that help him fly, and has made him exercise every day (mush to his displeasure).
Kirk truly likes spending time with Zahir, as he enjoys his magic tricks. However, he doesn't like it when he is the one tricked.
Kirk enjoys going on flight patrol with the harpy, as she can understand his love of flying.
He often helps her when she forgets stuff, and makes shore she pays attention to her current situation.
Though he dislikes her general attitude, Kirk thinks she is just a "tough girl, trying to hide her soft insides".
Though Jonny is technically the reason Kirk became a werebat in the first place (due to him offering Kirk the combinatory formula), Kirk doesn't blame the boy genius, stating that he would had done the same: not miss the chance to possibly be part of something greater.
The two get along very well with one another, often helping each other with their experiments. However, Jonny's cocky attitude sometimes annoys Kirk as well.