Rulings
Q1: What are the specific <Overflow X> rules for this card?
This card is always an inherent rule with trait: type "aquatic type".
Q2: When this card's End of Your Turn effect returns this card to the bottom of the deck, can I activate this card's Decode "Blue Lv.5" and then return an opponent's Digimon of Lv.6 or lower to the bottom of the deck?
Yes, it can be returned to the bottom of the deck after activating "Decode "Blue Lv. 5".
Q3: With this card's End of Your Turn effect, I tried to return this card to the bottom of the deck and return my opponent's "EX6-054 Lucemon: Chaos Mode" to the bottom of the deck. In this case, in which order can I activate this card's "Decode《Decode《青Lv.5》", the All Turns effect of "EX6-054 Lucemon: Chaos Mode", and the On Play effect of the card that appeared as a result of these effects?
This card's End of All Turns effect simultaneously triggers the All Turns effect of this card's "Decode《Decode《Blue Lv.5》" and "EX6-054 Lucemon: Chaos Mode". It is activated by interrupting from the turn player's "Decode《Decode《Blue Lv.5》", followed by the All Turns effect of "EX6-054 Lucemon: Chaos Mode". Once these effects are resolved, the On Play effects of the cards played by these effects are triggered simultaneously and are activated from the turn player's effects.
Data Sources
Lv.6 Ryugumon BT19-027 SR Mega | Data | Mollusk/LIBERATOR <Decode (Blue Lv.5)> (When this Digimon would leave the battle area other than in battle, you may play 1 level 5 blue Digimon card from its digivolution cards without paying the cost.) [When Digivolving] You may play 1 level 4 or lower blue Digimon card from this Digimon's digivolution cards without paying the cost. [End of Your Turn] [Once Per Turn] By returning 1 of your Digimon to the bottom of the deck, return 1 of your opponent's Digimon with as high or lower a level as it to the bottom of the deck. (Rule) Trait: Has [Aquatic] Type.
Lv.6 Ryugumon BT19-027 SR Mega | Data | Mollusk/LIBERATOR <Decode (Blue Lv.5)> (When this Digimon would leave the battle area other than in battle, you may play 1 level 5 blue Digimon card from its digivolution cards without paying the cost.) [When Digivolving] You may play 1 level 4 or lower blue Digimon card from this Digimon's digivolution cards without paying the cost. [End of Your Turn] [Once Per Turn] By returning 1 of your Digimon to the bottom of the deck, return 1 of your opponent's Digimon with as high or lower a level as it to the bottom of the deck. (Rule) Trait: Has [Aquatic] Type.
Lv.6 Ryugumon BT19-027 SR
Mega | Data | Mollusk/LIBERATOR
{{Decode|Blue|5}}.
[When Digivolving] You may play 1 level 4 or lower blue Digimon card from this Digimon's digivolution cards without paying the cost.
[End of Your Turn] [Once Per Turn] By returning 1 of your Digimon to the bottom of the deck, return 1 of your opponent's Digimon with level equal to or lower to your Digimon to the bottom of the deck.
(Rule) Trait: Has [Aquatic] type.Lv.6 リュウグウモン BT19-027 SR 究極体 | データ種 | 軟体型/リベレイター ≪デコード《青Lv.5》≫（このデジモンがバトル以外でバトルエリアを離れるとき、このデジモンの進化元から、青のLv.5のデジモンカード1枚をコストを支払わずに登場できる） 【進化時】このデジモンの進化元から、青のLv.4以下のデジモンカード1枚をコストを支払わずに登場できる。 【自分のターン終了時】[ターンに1回]自分のデジモン1体をデッキの下に戻すことで、戻したデジモンのLv.以下の相手のデジモン1体をデッキの下に戻す。 〈ルール〉特徴:タイプ「水棲型」を持つ。