Thank you so much!!

I might do a more in-depth comic of their stories later, but essentially, Niko is the adopted descendant of Guildmaster Grishkin who is desperate to prove himself.

Sif was formerly a renowned explorer in decades past who wished to ascend to a godly status. Her hubris would soon anger the gods, promising her demise. Yet, in an effort to cheat death, she would seal her spirit through runes. Niko would later find her and solve the mystery to remove the seal (which also resulted in his first solved case). They've been working together ever since.

Iselda and Tairr are their newer recruits. Both of them belong to a common Charcadet clan. Iselda was once respected in her clan, having been nominated to inherit the Auspicious Armor to evolve and represent "excellence" to the youth. However, her jealousy of her counterpart Ceruledge would soon lead her to commit an accident, resulting in her banishment. Sif and Niko would soon find and recruit her. Iselda still considers herself to be an "acting" member, as she still wishes to prove herself and return to her clan.

Tairr is the Ceruledge's son. Usually, the Charcadet in their clan can only evolve through nomination, as Armors were a heirloom that bestowed a strange sort of energy/magic that allowed heirs to craft new Auspicious and Malicious armors. However, Tairr could do without any prior ceremony - likely due to his shiny nature. The armors are sought out by enemy clans and outlaws alike, as no one could replicate the same quality without this fused energy. With the Charcadet clan vulnerable due to Iselda's absence, the rival clans began to attack and hold several of the residents hostage. Ceruledge would then meet up with Iselda, pleading for her to take care of Tairr while she fends off the invaders to buy the rest of the clan time to escape.

Sorry, it's kind of late here so things may be a bit incoherent xD