here's my theory about asta. sorry this is long because i have a lot of ideas about it but let me please know what do y'all think ( ◠‿◠ ) if u haven't read the manga, don't read it.
➜ from the backstory ep (123/124), seeing baby yuno and asta just give me ideas about asta's history. since they were put in the church at the same time and have their names written on their shirt already, means that someone knows them and watching over them. just like yuno, the guy who put him there at church came back and told him everything. now, this makes me really feel that asta is also from the spade kingdom because there was an uproar before caused by the dark triads, and given the fact that he has a name already before, means that someone might be waiting for the right time to go to him.
➜ what's more, on chapter 242, seeing gauche like that just triggered his mind and he just saw a memory from WHEN HE WAS A BABY. so my question is, how is he able to remember that? he was just a baby, but this thing made me think that he's incredible for remembering that, but if he can remember those things, maybe they really planned to stock his memory since he was a baby but sealed it. but why?? afraid that asta might know what he really is? why do i also feel like since he was born he already had a demon and that demon sealed his memories or maybe that demon attacked his mom or maybe the demon protected asta when he was a baby and his mom asked him to take care of asta??🤔
➜ another one, let me just remind y'all, his black headband, it was with him ever since, the symbol is similar to dark triad. just like yuno, he has magic stone that was given to him. so maybe asta's headband was an evidence that he might be related to them. but if the line symbol JUST SHOWS because of the possession of the devil and getting added when they power up (if you noticed the lines were added), it means that asta might already be possessed by devil because when he doesn't have his grimoire, he already wearing it and has those symbol. however, from the backstory episode, secre (nero) said that she sees asta so she gave him the grimoire of licht that she sealed when he turned into a demon. but they said that the grimoire has a different devil in it (if you remember what the devil said during the elf arc). idk what the devil from the elf arc meant but i feel like if asta is already possessed by devil (cause of the line symbol on his headband) does that mean the devil on him went to the grimoire and make them compatible?? or maybe he has two devils? a human demon (asta) and a demon from the grimoire?? as you can see he has like 3 horns. the demon in the grimoire has two. so where does the other two came from??🤔 as i remember the devils want to obtain a physical body, so what if asta is already a demon in a physical form and he is just still unaware of it.
➜ i also remember from the jump festa 2016, the guy who attacked them before (it's also from the first episodes) said that "the grimoire chooses his master." so if the grimoire do that, does that mean if they're not compatible, there's no way that he can be able to use it? but the grimoire go to asta, means that he might be related to devils. as i remember from the witch queen before, she said that "a sudden mutation kept the mana from dwelling to him. makes him deflective and able to wield the sword." so it's like it's showing us that asta is the choosen one to really use it. just like i said, he might already be possessed by a devil and his devil went to the grimoire making asta able to use the swords and grimoire (maybe). also, what if asta's dad is part of the dark triad? or maybe his dad is cursed? and remember that spade kingdom stole magic powers from their people? there's a possibility that asta's magic abilities was also stolen but the possibility of him being related to a devil has a higher percentage.
P.s this is just my theory based on what i've seen so far. we don't know what might happen. that's up to tabata but if some of what i thought might be correct then that would literally blow my mind.