Death Coins
Death Coins are handed out by several redemption codes — the update9 code grants 30 Death Coins and the title code adds another 20, both cross-verified across four gaming-media sources. What Death Coins specifically purchase in-game is not detailed in any source checked for this page, so treat their exact use as unconfirmed until verified in-game.
Weapon Stones
Weapon Stones are used to purchase and upgrade swords along the Death Road, according to Pro Game Guides and gamestratwiki. Some codes have reported Weapon Stones as rewards, but their current active status is disputed between sources, so check the codes page before counting on them.
Soul Ring Rerolls
This currency lets you reroll a Soul Ring's stats, and gamestratwiki recommends spending it only on rings pulled from deeper Death Tower floors. It's reportedly earned from the Shadow Clash event and, according to some but not all sources, from specific codes.
Prays
Prays are handed out by the guildtest code (5 Prays) and the happybirthday code (10 Prays), both confirmed across four gaming-media sources. As with Death Coins, no source checked for this page specifies what Prays are spent on in-game.