Dude's dad remarriage the two sisters mother so they are his step-sisters.
But their hair color are similar enough to be real siblings.
Production team just too lazy to give the dude different hair color. lol ---------- wtf p.53, p.54 younger sister eyes changed color... is that double end dildo or she grown dick cause of that eye color?
If I recall, the younger sister "loli" is actually the older sister and she is a succubus, or has some succubus blood, and in that end, her libido goes crazy and the other sister is head over heels over her sister since she fucks her crazy all the time and hasn't had sex with MC, he only realizes he got cucked after loli refuses him any sex and will only allow him to masturbate while watching them go at it which is the CG in question - Male MC's only use is his income and house chores since all the sisters do is fuck.