If your opponent controls a monster and you control no other monsters: You can target 1 Fusion Monster in your Graveyard; banish both that target and this card, and if you do, Special Summon 1 Dragon-Type Synchro Monster from your Extra Deck whose Level equals the total Levels of the banished monsters. You cannot Special Summon monsters the turn you activate this effect, except Dragon-Type monsters. You can only use this effect of "Hellfire Boatwatcher, Ghost Charon" once per turn.