Main Characters

Sowon as Akira Khia S. Calliope (Sowon)

SinB as Ashianna Faith B. Celeste (SinB)

Calliope means 'Beautiful Voice'

Celeste means 'Heavenly'

Side Character

Keira D. Knightley (Yerin)

Samantha D. Knightley (Eunha)

         -Keira's Younger Sister-

Kirsten Misty M. Calista (Yuju)

Calistine S. Calliope (Umji)

         -Akira's younger Sister-

Additional Character

Arturo Leo M. Celeste (Ashianna's dad)

Dorothy B. Celeste (Ashianna's mom)

Zachary Theo B. Celeste (Ashianna's older brother)

THE characters full name 

Akira Khia 'Samson' Calliope

Ashianna Faith 'Belnas' Celeste

Keira 'D'Agostina' Knightley

Samantha 'D'Agostina' Knightley

Kirsten Misty 'Magbanua' Calista

Calistine 'Samson' Calliope

Arturo Leo 'Maxton' Celeste

Dorothy 'Belnas' Celeste

Zachary Theo 'Belnas' Celeste 

The meaning of the Title (I wrote the meaning myself, hehehehe)

"Eternal Echoes of Love"

It captures the girl's best friend's developing emotions as well as the persistent recollection of the former girlfriend

Tagalog

Nakukuha nito ang namumuong emosyon ng matalik na kaibigan ng dalaga pati na rin ang patuloy na pag-alala sa dating kasintahan.