By spending Hades’ Chthonic Keys, you’ll eventually unlock six unique weapons, called Infernal Arms.
Each weapon possesses unique attributes, including its own fire or strike, a dash-strike, a special move, and a cast. As you roam the underworld, you acquire temporary upgrades on each run to customize your weapon so it is more effective. Permanent upgrades are also available, using a rare item called Titan Blood.
You earn Hades’ Titan Blood the first time you defeat the boss at the end of the first region using any one of the Infernal Arms. Thereafter, you will receive lesser rewards while using that particular weapon until you manage to escape the underworld. Once you have obtained Titan Blood for the first time, you can trade to acquire more of it by visiting the Wretched Broker.
Aspects: Upgrading weapons with Titan Blood
In Hades, the purpose of Titan Blood is to upgrade weapon abilities called Aspects. Take, for example, the Varatha spear. It has the Aspect of Zagreus, which increases damage, range, and speed. The Aspect of Achilles allows Zagreus to throw his spear, and then rush to it and immediately deal more damage in battle with his next few strikes. Every weapon has four upgrades you can eventually unlock and upgrade.
To upgrade a weapon’s Aspects, you must first equip that weapon in the room occupied by Skelly the training dummy. Grab the desired weapon from its pedestal, and then inspect the pedestal to make your enhancement, provided you have enough Titan Blood. Some of the more costly enhancements cost several Titan Blood apiece.
While you are viewing your weapon, you can also choose which Aspect to equip. Zagreus can only equip a single Aspect at a time. Aspects tend to reward you when you commit fully to a particular weapon’s approach.
When you are in the chamber with Skelly just before starting your next run, pay attention to the various weapons. One of them is always enshrouded in swirling black and purple light. Equip that weapon for your next run to increase Darkness shards and gemstones awarded along the way. This is your opportunity to try mastering different weapons while earning greater rewards.