If you end up with 0 cards left when Bonz has not yet used his tribute to the doomed, you can use Interdimensional Matter Transporter transporter to banish one of your monsters so you can summon vassal.
Once you manage to summon Sphynx, activate its effect to send unnecessary cards to the graveyard, and special summon more fire monsters to your field for your Beast Rising.
Make sure that you don't activate Sphynx's effect to discard your Vassal, Union Attack, and Secret Pass to the Treasures. But if you did, then try to end the duel with your Sphynx, or use Windstorm to switch his monsters to attack position if he has any face up monsters and attack into it.
Do not set 2 spell/trap cards at a time to avoid being locked by his Xing Zhen Hu. But you can use Hazy Glory's effect to clear some space if it happens.
I'm almost lack of keys from Mai to Bonz, swrordswoman to Ghostrick witch. I finally got my 3rd swordswoman and 4th unintentionally. But Ghostrick witch doesn't like me. why is it so hard for me to obtain her?
Do NOT use the Sylvan deck against Bonz! It doesn't work for s**t against him, Tribute to the Doomed and an overpowered King of the Skull Servants wreck your chances of dealing the finishing move with this deck post ban list.