@Elain an alpha who can get alphas pregnant. Taeju's blonde dad is an enigma (although it was not specified since alphas who can impregnate alphas are still called alphas rather than enigmas)
BL Recommendations
Spoiler!
https://docs.google.com/spreadsheets/d/1mZ1odzyGGFo534EQwherPU0qyzEMAo1MPHTL8k4AFew/edit?usp=drivesdk