

Q1: If I don't delete an opponent's Digimon for this card's Main effect, can I use the part of the effect after "then" to have this Digimon attack?
Yes, it can attack.
Q2: Can I pay just 1 cost for this card's Main effect?
No, you can't. A "by" condition can't be met if only some of the required actions are performed. The conditions for this Main effect require you to pay 3 cost.
Q3: Can I process the part of the effect after "then" in this card's Main effect without meeting the "by" condition?
No, you can't. If you don't pay 3 cost, the part after "then" in this card's Main effect won't let this Digimon attack.
Q4: My opponent has a level 5 or lower Digimon. Can I meet the "if this effect didn't delete" condition in this card's Main effect by not choosing a card to delete?
No, you can't. If your opponent has a level 5 or lower Digimon, you must choose that card and delete it.
Q5: My opponent has a level 5 or lower Digimon. Can I meet the "if this effect didn't delete" condition in this card's Main effect by choosing an opponent's level 5 or lower Digimon with an effect that prevents deletion?
Yes, you can.
Q6: Can I activate this card's Main effect even when my opponent doesn't have any Digimon that can be deleted?
Yes, you can.
Lv.5 SkullMeramon BT22-074 U Ultimate | Data | Flame/CS [Main] [Once Per Turn] By paying 3 cost, delete 1 of your opponent's level 5 or lower Digimon. If this effect didn't delete, this Digimon gains <Security A. +1> for the turn. Then, this Digimon may attack. [On Deletion] <Draw 2> and trash 1 card in your hand. --- [On Deletion] You may play 1 level 4 or lower Digimon card with the [Flame] or [CS] trait from your trash without paying the cost.
Lv.5 SkullMeramon BT22-074 U Ultimate | Data | Flame/CS [Digivolve] Lv.4 w/[Flame]/[CS] trait: Cost 3 [Main] [Once Per Turn] By paying 3 cost, delete 1 of your opponent's level 5 or lower Digimon. If this effect didn't delete, this Digimon gains <Security A. +1> for the turn. Then, this Digimon may attack. [On Deletion] <Draw 2> and trash 1 card in your hand. --- [On Deletion] You may play 1 level 4 or lower Digimon card with the [Flame] or [CS] trait from your trash without paying the cost.
Lv.5 SkullMeramon BT22-074 U ultimate | Data | Flame/CS [Digivolve] Lv.4 w/[Flame]/[CS] trait: Cost 3 [Main] [Once Per Turn] By paying 3 cost, delete 1 of your opponent's level 5 or lower Digimon. If this effect didn't delete, this Digimon gains <Security A. +1> for the turn. Then, this Digimon may attack. [On Deletion] <Draw 2> and trash 1 card in your hand. --- [On Deletion] You may play 1 level 4 or lower Digimon card with the [Flame] or [CS] trait from your trash without paying the cost.
Lv.5 デスメラモン BT22-074 U 完全体 | データ種 | 火炎型/CS 【メイン】[ターンに1回]3コスト支払うことで、Lv.5以下の相手のデジモン1体を消滅させる。この効果で消滅しなかったなら、ターン終了まで、このデジモンは≪Sアタック+1≫を得る。その後、このデジモンでアタックできる。 【消滅時】≪2ドロー≫し、自分の手札1枚を破棄する。 --- 【消滅時】自分のトラッシュから、特徴に「火炎型」/「CS」を持つ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。