Well his father was sombra he met the princesses at a very young age received training from both as well as his father, they were dear friends of his and when sombra went mad

he pleaded the sisters to help but his father seen this as his own son being a traitor.. long story short after celetia banished sombra, Callos chose to protect the two. But things didn't

go well when he confessed how he felt and was just told it was a childhood crush and nothing more and that it should be left alone.. though it was no crush he really had fallen in love

with the two because he seen they were not emotonless and had feeling and hurt like everyone else.. he felt they were more then some goddess they were like him and he felt they needed

love like anyone else.