Dong-yeong, introduced in Seven Knights Re:BIRTH, is a Magic-type hero who pressures enemies using Deadly Poison and Fear, while providing shields and increased Magic damage to allies. More than just adding raw damage, Dong-yeong serves as a core piece that boosts both the survivability and sustained pressure of Magic decks.

The key is the passive skill 'Companion of the Underworld.' Dong-yeong’s Effect Accuracy increases in proportion to Attack, and they revive in an Indomitable state upon death. They provide increased Magic damage to all allies and support ally HP recovery whenever Indomitable is triggered. For Magic decks, this covers damage, survival, and utility all at once.

The most notable effect is the follow-up attack that triggers every time allies use two skills. It deals damage to all enemies and applies both Deadly Poison and reduced healing received. Because this effect triggers repeatedly during battle, it is particularly helpful when facing defensive decks that rely on sustain.

Deadly Poison is also essential to understanding Dong-yeong. It is a poison-type effect that deals damage proportional to the target's max HP every turn. This helps in taking down high-HP opponents and can quickly deplete the immunity stacks of offensive deck heroes. Combined with 'Touch of the Abyss' to inflict Fear, Dong-yeong can pressure opponents in various ways. The turn-based buff reduction on the Ascension skill is also a major asset.

Dong-yeong’s main stage is PVP. They are used as a core hero in content where Magic decks are viable, such as the Arena, Advanced Arena, and Total War. Before Dong-yeong’s arrival, Magic decks struggled against offensive and defensive decks, but since joining, they have been showing renewed strength in PVP.

Against defensive decks, the reduced healing received and Deadly Poison are key. Defensive decks often use high HP, healing, immortality, and authority to stall. Dong-yeong accumulates healing reduction every two ally skills and applies continuous damage via Deadly Poison to erode the opponent's sustain. It is a strategy of attrition, wearing the enemy down while suppressing their recovery.

Dong-yeong is also helpful against offensive decks. For damage dealers equipped with survival tools like damage immunity, Dong-yeong is useful for stripping away those defenses using Deadly Poison and the passive follow-up attack. The 1-turn damage immunity provided to allies in the same row also helps withstand heavy incoming damage. In fact, while the skills seem more impactful against defensive decks, many players feel they perform even better in offensive deck matchups.

They can also be deployed in PvE. When placed in a Magic deck for stage progression like Adventure or the Tower of Infinity, Dong-yeong can easily pull their weight as a sub-damage dealer. Their utility is exceptional, and since all their skills are useful, they have the potential to be used in various content. As a side note, Dong-yeong can solo-clear even the 15th floor of the Water Element Dungeon.

Magic decks featuring Dong-yeong are often built around Freya and Reginleif. Both heroes were already staples in existing Magic decks and have great synergy with Dong-yeong. The remaining slots are typically filled by heroes like Melkire, Skuld, Omok, Yeonhee, or Silvester, allowing for various combinations depending on your preference.

The synergy with Melkire is particularly noteworthy; Dong-yeong’s passive triggers every two ally skills, allowing for the accumulation of Melkire’s Magic Backflow damage. While neither hero has a massive 'one-hit' burst, they are excellent at continuously stacking damage and pressuring the opponent.

The most standard combination is likely Dong-yeong, Freya, Reginleif, Melkire, and Omok. This is a popular choice in the Arena, Advanced Arena, and Total War. Melkire’s passive, which reduces all enemies' Effect Resistance, also benefits Dong-yeong. Omok supports the team with a Magic attack power increase passive and a guardian spirit, while also providing decent personal damage and a passive shield. Skuld is also used; although her passive overlaps with Melkire’s, her versatility makes her a strong pick.

Yeonhee is sometimes included in this season's Advanced Arena, where accessory restrictions are in effect.

Dong-yeong’s equipment settings vary by player. Generally, the essential options to secure are Speed, Effect Accuracy, and Effect Resistance. Dong-yeong can gain up to 45% Effect Accuracy through their passive, which is easily achievable once you reach 27 million Attack. You should then use equipment to boost Effect Accuracy as much as possible.

Effect Resistance is also highly important. Dong-yeong needs to attack consistently without being disrupted to perform at their best. Since recent PVP content features many threatening CC effects, it is best to prioritize Effect Resistance to prevent them. While Speed is a staple for Magic decks, many players are now investing in internal stats since Dong-yeong’s release, so the priority may shift depending on your accessories.

The Avenger set is the most commonly recommended. Since Dong-yeong’s influence grows as the battle drags on due to Deadly Poison and follow-up attacks, the Avenger set is a solid choice to capitalize on continuous damage and pressure. However, due to Aris' presence in defensive decks, the importance of Crit chance has increased, which can make it difficult to balance Effect Accuracy, Effect Resistance, and Crit chance all within an Avenger set.

Therefore, the Assassin set is a viable alternative. You should look at Crit chance, Effect Resistance, and necessary Effect Accuracy as your priority options. While the best approach is to use All Attack % on armor and secure Effect Resistance in sub-stats, this can be difficult to set up. Until you have high-quality gear, using two Crit chance weapons and two pieces of Effect Resistance armor to secure the core stats is a perfectly fine approach.

Dong-yeong is a hero who can be deployed even at relatively low Transcendence levels. Their core utility is not affected by Transcendence, and reaching just Transcendence 2 adds a damage immunity effect for allies in the same row. At Transcendence 4, they gain a 24% Effect Accuracy stat boost, which helps with equipment settings.

That said, Transcendence 6 is still important. It grants a 20% Magic vulnerability to all enemies, increasing damage output and opening up options for Skuld combinations. It also increases the hit count for Dong-yeong’s Indomitable effect when an ally dies, further enhancing survivability. If you focus on PVP with a Magic deck, I recommend reaching Transcendence 6 before the pickup ends, but if resources are tight, aim for Transcendence 2 or 4 for now. If your goal is moderate performance in Total War, they will help manage your Magic deck's win rate even without Transcendence 6.