Soul Heirloom

Soul Heirloom is a system derived from the original system of Spirit Siphon. Basically Soul Heirloom is a system that increases a Vassal's Level Cap, Basic Stats, and Skill Effects through Resonantia.

• Consume Vassal Spirits to perform Spirit Siphon. Vassal Spirits can be obtained via [Embrace], [Puppet Association], and other channels.
• Each [Spirit Siphon] increases the Vassal's Basic Stats.

After Spirit Siphon, the Vassal's Level Cap can be increased:

• SR Vassal Level Cap can be increased to up to LV. 160 (Spirit Siphon Tier 2)
• SSR Vassal Level Cap can be increased to up to LV. 200 (Spirit Siphon Tier 3)

Note: Spirit Siphon are vassal dupes, Each SSR Vassal are capable of reaching up to Spirit Siphon Tier 10, SR Vassal are capable of reaching up to Spirit Siphon Tier 2 and R Vassal does not have Spirit Siphon Tiers.

After Spirit Siphon reaches a specific Tier, you can unlock the Vassal's Resonantia effects in the Soul Heirloom. Specific Vassals are given with these new effects and modifiers to their skills and give them more basic stats such as HP, All DMG Reduction, Crit Resist Rate, ATK, P. Def and M. DEF.

As you can see, Vassals that have Resonantia available have a generic Resonantia Node for Tier 3 (Blood Memory) and Tier 9 (Severance), these two nodes provide basic stats. While Tier 1, Tier 5 and Tier 7 vary on its effects depending on the Vassal.

The Heirloom Vault can be upgraded and broken through by consuming specific materials. Each Vault upgrade/breakthrough increases the Vassal's Basic Stats. After the Vault reaches a certain Breakthrough Level, the values of the Soul Heirloom's Resonantia effects will be further improved.

The materials can be obtained in a resource dungeon raid called Void of Shadow, please refer to the link for more info about Void of Shadow:

Void of Shadow Guide