Rulings
Q1: If this card's 1st effect and a "when a card is removed from ... security stack" effect trigger simultaneously when this card is trashed from the security stack, in what order do they activate?
The turn player activates their effect first. If both effects are the turn player's, they can activate them in any order.
Q2: What is a {Security} effect?
A {Security} effect can be triggered/activated while its card is face up in the security stack. Such effects can't be triggered or activated in areas other than the face-up security cards.
Q3: I have multiple copies of this card face-up in my security stack. When my Digimon with Renamon, Kyubimon, Taomon, or Sakuyamon in its name would leave the battle area other than by battle, I activate the {Security} All Turns effect on the 1st copy of this card, and that Digimon is prevented from leaving. Can I then activate the {Security} All Turns effect on the 2nd copy of this card?
Yes, you can. The {Security} All Turns effects on the 2 copies of this card trigger simultaneously when your Digimon with Renamon, Kyubimon, Taomon, or Sakuyamon in its name would leave the battle area other than by battle. After activating the effect on the 1st copy, the Digimon is prevented from leaving, then you can activate the {Security} All Turns effect on the 2nd copy of this card. After that, the 1st effect on the 2 copies of this card will trigger simultaneously, and you can activate them one at a time for a total of 2 activations.
Q4: I have this card placed face-up in my security stack. If this card's {Security} All Turns effect activates when multiples of my Digimon with Renamon, Kyubimon, Taomon, or Sakuyamon in their names would leave the battle area other than by battle, then this card is trashed from the security stack, what happens?
You choose 1 of your Digimon with Renamon, Kyubimon, Taomon, or Sakuyamon in its name, and that Digimon is prevented from leaving the battle area. If you have another face-up copy of this card in your security stack, the {Security} All Turns effects on those copies will also activate, and you can choose 1 more Digimon that will be prevented from leaving.
Data Sources
Amethyst Mandala ST22-10 SR
Onmyōjutsu
When effects trash this card from the security stack, activate its [Security] effects.
{Security} [All Turns] When any of your Digimon with [Renamon], [Kyubimon], [Taomon] or [Sakuyamon] in their names would leave the battle area other than in battle, by trashing this card, 1 of those Digimon doesn't leave.
[Main] <Draw 1>. Then, place this card face up as the bottom security card.
---
[Security] 1 of your opponent's Digimon gets -9000 DP for the turn.Amethyst Mandala ST22-10 SR
Onmyojutsu
When effects trash this card from the security stack, activate its [Security] effects.
{Security} [All Turns] When any of your Digimon with [Renamon], [Kyubimon], [Taomon] or [Sakuyamon] in their names would leave the battle area other than in battle, by trashing this card, 1 of those Digimon doesn't leave.
[Main] <Draw 1>. Then, place this card face up as the bottom security card.
---
[Security] 1 of your opponent's Digimon gets -9000 DP for the turn.Amethyst Mandala ST22-10 SR Onmyōjutsu When effects trash this card from the security stack, activate its [Security] effects. (Security) [All Turns] When any of your Digimon with [Renamon], [Kyubimon], [Taomon] or [Sakuyamon] in their names would leave the battle area other than by battle, by trashing this card, 1 of those Digimon doesn't leave. [Main] <Draw 1> Then, place this card face up as the bottom security card. --- [Security] 1 of your opponent's Digimon gets -9000 DP for the turn.
金剛界曼荼羅 ST22-10 SR
陰陽術
このカードがセキュリティから効果で破棄されたとき、このカードの【セキュリティ】効果を発揮する。
{セキュリティ}【お互いのターン】名称に「レナモン」/「キュウビモン」/「タオモン」/「サクヤモン」を含む自分のデジモンがバトル以外でバトルエリアを離れるとき、このカードを破棄することで、そのデジモン1体は離れない。
【メイン】≪1ドロー≫。その後、このカードをセキュリティの下に表向きで置く。
---
【セキュリティ】ターン終了まで、相手のデジモン1体をDP-9000。