# Tiers & Grades

**‘Tier'** defines the rarity of an agent.

The rarity of an agent is split into five categories. Among them, Epic and Legend agents have a chance of obtaining a Unique Skill.

Each agent has a fixed ‘Tier’ and therefore an agent's ‘Tier’ cannot be changed once it is determined upon aquisition.

* **Tier 1: Legend**
* **Tier 2: Epic**
* **Tier 3: Rare**
* **Tier 4: Uncommon**
* **Tier 5: Common**

***

**‘Grade’** refers to the Star Grade of an agent.

An agent’s ‘Grade’ can be increased up to five stars, and at higher ‘Grades’, the agent will have higher stat growth potential. An agent’s ‘Grade’ can be increased by using the ‘Promotion’ system.

* [**Agent Growth - Grade Up**](/desperado-b218-the-scars-of-exos-en/ecosystem/agent-growth/grade-up.md)


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