Do you ever ever think about how Guy is the only one who TRULY understands Ramiris.
He knows what she went through and what she is going through (her reincarnation cycle). He defends her and has treated her as an equal despite being so strength obsessed. Guy does not respect those who are weak. He barely gives them the light of day. But ramiris, the weakest of the octagram in her current state, is his close friend. He threatened to kill his best friend (Leon) (who bro is literally attracted to) when he spoke poorly about Ramiris. Ramiris, who is largely shunned and underestimated, is perfectly understood by Guy. He looks past her cocky attitude. He knows who she once was. They stopped Milim together, after all. Ramiris sacrificed her prime for Milim and him. If Ramiris hadn't intervened. Hadn't taken in those corrupted magicules. Guy would have had to.
There's no way of knowing if that would have affected Guy in much capacity. But Guy was tired. He had fought Milim, a match, for seven days and nights. He might have lost. Or he could have won. There is really no way of knowing. Ramiris 'saved' them either way.
He knows that, despite Ramiris slowly degrading memory, she will always be herself and remember after each lifetime. He knows that she may not have the appearance, but she's still the same ramiris. People think Ramiris is stupid, but Guy knows she is one of the smartest. He let's her talk for hours on end. He let's her sit beside him. That's insane. Guy, the literal embodiment of pride, let's a tiny pixie sit beside him in the demon lord council.
The trust they hold with each other is also unbelievable. Guy trusted Ramiris with the decision to allow Rimuru to, basically, exist. She isn't scared of Guy either, like how most people are. Sure, she had said that "Guy is the only demon lord I won't fight" in a fearful-ish way. But that wasn't the fright that Guy often instils. She isn't scared of him. She isn't in fear of ticking him off.
Ramiris has no qualms going straight towards Guy during Walpurgis. She bickers with him. Guy wouldn't ever allow someone to talk like that to him. Except Ramiris.
They know each other. He knows her not as the Spirit Queen or as the annoying pixie, but as Ramiris. She knows him not as Demon Lord Guy Crimson but as Guy.
I really truly believe that they're eachothers actual best friends. Guy would fight Leon, his supposed best friend. He would not fight Ramiris. Rimuru often underestimates Ramiris and treats her as an aloof child. Guy doesn't. At least, not internally.
Guy has teased, of course. Rimuru does recognise Ramiris as a smart and useful person. But it's easily inferable that Rimuru still knows her as, well, annoyingly childish to most people.
Ramiris is the only person who can treat Guy the way she does. The only others that have been shown to be able to are Milim and MAYBE Leon. Leon has shoved Guy, a playful gesture for Guy, even in Leon's annoyance. But to bicker and contradict Guy, the way Ramiris does takes a lot. Their friendship isn't just that. But it's a connection. Ramiris and Guy are immortal and ancient, who both respected Veldanava, who both treated his daughter as one of them, who are two of three ancient DLs.
Ramiris was never a proper demon lord to begin with. She is unable to evolve into a True DL like rimuru or milim. She doesn't have the strength like Leon or Dagruel. She joined the council because of the respect Guy had for her. The gratitude he had for her.
Satan's best friend is a small pixie. The Spirit Queen's best friend is a demon.
