Charalampos 'Babis' Kostoulas joined Albion from Olympiacos in July 2025.
The striker signed a five-year deal.
Kostoulas graduated through the Olympiacos academy and in the 2024/25 season helped them win the Greek league and cup double. He scored seven goals and provided two assists in 35 appearances across domestic competition and the Europa League.
He has also scored five goals in 15 appearances for Greece at under-16 to under-21 level.