Unlock Weapons
Kintoki's second weapon (Blazing Axe):
Complete stage 8 as Kintoki
Raikoh's second weapon (Divine Blade):
Complete stage 14 as Raikoh

Sadamitsu's second weapon (Shrieking Blossom):
Complete Havoc Mission 4

Seimei's second weapon (Twin Dragons):
Complete stage as Seimei

Suetake's second weapon (Eight Truths):
Complete Havoc Mission 7

Tsuna's second weapon (Thunder):
Complete stage as Tsuna

Tsuna's third weapon (Wrath):
Purify both Centipede Demons in Stage 22
Suetake's third weapon (Divine Punishment):
Complete Havoc Mission 13
Sadamitsu's third weapon (Black Wings):
Complete stage 20 in 2.5 minutes
Raikoh's third weapon (Falling Star):
Complete Havoc Mission 17
Kintoki's third weapon (Red Lotus):
Complete Havoc Mission 12

Raikoh's fourth weapon (Moonlight Sword):
Buy it from the shop during 2nd play for 317,000 gold.