This guide details how to obtain and utilize the powerful Dark/Dragon-type Pokémon Hydreigon in Pokémon Scarlet and Violet. Hydreigon, a pseudo-legendary Pokémon, boasts impressive stats and is a valuable asset to any team. However, its evolutionary line (Deino and Zweilous) is exclusive to Pokémon Scarlet.
Acquiring Deino:
Deino and its evolution, Zweilous, can be found in various locations within Pokémon Scarlet:
- Alfornada Cavern: Located in the southwest corner of the Paldea region. Koraidon's high jump ability is necessary to navigate this area.
- Dalizapa Passage: Situated between Medali and Zapapico.
- Glaseado Mountain: A readily accessible mountain range.
- Area Zero: The endgame area.
- North Province (Area Two): Another easily accessible area.
Deino and Zweilous also appear in Tera Raids: 3-star raids for Deino and 4-star raids for Zweilous. These offer a chance for Pokémon with different Tera Types and potentially Hidden Abilities. Hydreigon can be found in 5-star and 6-star Tera Raids.

Transferring Deino to Pokémon Violet:
Since Deino is exclusive to Pokémon Scarlet, players of Pokémon Violet must obtain it through trading or transferring via Pokémon HOME. Trading requires a Nintendo Switch Online membership, while Pokémon HOME allows transfers from other compatible games (Pokémon Sword/Shield, Pokémon GO, Pokémon Scarlet). The HOME method is detailed below:
- Move Deino from your source game to your Basic Box in Pokémon HOME.
- Open Pokémon Violet in HOME and transfer Deino to a PC Box.

Evolution:
Deino evolves into Zweilous at level 50, and Zweilous evolves into Hydreigon at level 64. Utilize auto-battling or Exp. Candies (especially L and XL) to expedite the leveling process.
Hydreigon's Strengths and Weaknesses:

Hydreigon's base stat total is 600, with high Special Attack and Attack, and good Speed. A Timid or Jolly Nature is recommended.
| Stat |
Base Stat |
| HP |
92 |
| Attack |
105 |
| Sp. Attack |
125 |
| Defense |
90 |
| Sp. Defense |
90 |
| Speed |
98 |
| Total |
600 |
Type Effectiveness:
- Super Effective Against: Dragon, Ghost, Psychic
- Weaknesses: Fairy (4x), Fighting, Bug, Dragon, Ice
- Resistances: Grass, Water, Fire, Electric, Ghost, Dark
- Immunities: Ground, Psychic
Hydreigon's significant weakness to Fairy-type moves can be mitigated through Terastallizing. Offensively, Terastallizing allows for STAB (Same-Type Attack Bonus) on powerful moves like Flash Cannon (learned via TM). Hydreigon's movepool allows for both physical and special attacking strategies. Recommended moves include Nasty Plot, Dragon Pulse (or Draco Meteor), Dark Pulse, and Flash Cannon.