Duelist Challenge #5 Solution
1. Summon Mermail Abyssturge from your hand
2. Activate the effect of Mermail Abyssturge
3. Discard Mermail Abysshilde
4. Add Mermail Abyssgunde from your graveyard to your hand
5. Activate the effect of Mermail Abysshilde
6. Summon Mermail Abyssmegalo from your hand
7. Activate the effect of Mermail Abyssmegalo
8. Tribute Mermail Abyssturge
9. Summon Mermail Abyssbalaen by discarding the other 4 monsters in your hand
10. Select every card on your oppoent's field to destroy
11. Activate the effect of Mermail Abyssgunde (chain to 10)
12. Summon Mermail Abyssleed from your graveyard
13. Change to battle phase
14. Attack directly (attack twice with Mermail Abyssmegalo)
Done :)