# 2022 Digimon Theme Booster Alternative Being #EX4-021

> GreyKnightsmon is a Level 6 Mega Dark Knight from the 2022 Theme Booster Alternative Being expansion, featuring powerful disruption and recursion abilities.

Canonical URL: https://supercatch.com/product/digimon-theme-booster-alternative-being-greyknightsmon-ex4-021-sr

## Identity

- **Year**: 2022
- **Manufacturer brand**: Digimon
- **Set / series**: Theme Booster Alternative Being
- **Card number**: #EX4-021
- **Product type**: TCG_CARD

## Description

GreyKnightsmon serves as a formidable presence in the Digimon Card Game, representing the peak of digital evolution as a Level 6 Mega Digimon. Released in 2022 as part of the Theme Booster Alternative Being expansion, this SR rarity card is cataloged as EX4-021 within the set. Players who build decks around the Dark Knight archetype often seek this card for its dual-color Blue and Black attribute, which allows for versatile gameplay strategies involving Virus-type attributes. The strategic value of GreyKnightsmon lies in its robust effects. Upon playing the card, it triggers a De-Digevolution effect that reduces an opponent's Digimon by one level, immediately weakening their board presence. Additionally, it prevents all opponent Digimon of Level 4 or lower from attacking until the end of their turn, providing significant defensive control during critical moments. This disruption capability makes it a favorite among collectors who appreciate tactical depth in the TCG. Beyond its defensive capabilities, GreyKnightsmon offers a unique recursion mechanic. Throughout the game, if this Digimon is deleted or returned to the hand or deck, players may activate an effect to play one MetalGreymon and one DarkKnightmon from its digivolution cards without paying the memory cost. This ability allows for resource recovery and continued pressure on the opponent, embodying the resilient nature of the Twilight and Blue Flare types. For collectors, owning a copy of EX4-021 adds a distinct piece of the Alternative Being narrative to their collection, highlighting the intricate design and mechanical complexity of the Digimon Card Game's later expansions.

## FAQ

### What type of Digimon is GreyKnightsmon?

GreyKnightsmon is a Level 6 Mega Digimon of the Dark Knight and Blue Flare types. It carries the Virus attribute and features both Blue and Black colors in the Digimon Card Game.

### What are the main effects of GreyKnightsmon EX4-021?

Its On Play effect De-Digivolves an opponent's Digimon and stops lower-level Digimon from attacking. Its All Turns effect allows you to play MetalGreymon and DarkKnightmon from its digivolution cards for free if it is deleted.

### Which set does GreyKnightsmon belong to?

This card is from the Theme Booster Alternative Being expansion, released in 2022. It is identified by the set code EX4 and card number 021.

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## Companion files

- [llms.txt](https://supercatch.com/llms.txt) — site-level concise index.
- [llms-full.txt](https://supercatch.com/llms-full.txt) — site-level expanded corpus.
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Last verified: 2025-11-29.