Of all of the design spirits that Ves had in his arsenal, Ylvaine's spiritual fragment was the most human. It didn't originate from an exobeast like Qilanxo. It wasn't a spiritual product either.
Born in a different time and age, Prophet Ylvaine rose up in the galactic heartland to become a visionary to countless people who had lost hope during those times.
Though the prophet was long dead, Ves managed to revive a trace of his existence and amplify it into a powerful spiritual fragment.
While not as strong as the Solemn Guardian, Ves never underestimated it. Unlike the Solemn Guardian, In its role as a design spirit, Ylvaine's spiritual fragment formed a lot of intimate connections with its mech pilots.
"Every Ylvainan mech pilot devote their heart and souls to their faith!"
As a consequence, every Ylvainan mech pilot unintentionally aligned their thoughts and emotions to the mechs they piloted.