The "Angel" cards

The "Angel" Set

Angels are monsters of two attributes: LIGHT and DARK. LIGHT attribute Angel Monsters favorite the flipping of face-down monsters to face-up and DARK attribute monsters vice-versa. In either case, they gain their effects from switching their battle positions from face-down defense position to face up attack position. While they are incredibly easy to counter (put in a real Yugioh TCG context), their effects can be devastating if chained correctly

Their monsters each start with "Angel - " and then are followed by a (usually abstract) name.
Their trump cards (3 of number) are Synchro monsters and each start with "Archangel - "

Monsters:

Angel - Aspect of the Vampire

When this monster is flipped face up from face-down defense position and is not destroyed by battle, flip it face-down and destroy up to 1 monster on the field

Angel - Endarkened Light

This monster's attribute is also treated as DARK. Once per turn, during your Main Phase, if another monster has been flipped face-down this turn, you may flip this monster face-down to destroy up to 1 Spell or Trap Card our opponent controls

Angel - Flash Striker

Whenever this monster would be flipped to face-down defense position, change it to face-up attack position instead and remove one card in your opponent's Graveyard from play. If this monster would be used for a Synchro summon of an "Archangel Monster", flip up to 1 monster on the field to face-down defense positon

Angel - Gracebringer

When this monster is flipped face-up from face-down defense position, you may flip another monster from face-down defense position to face-up attack position. During the turn this monster was flipped from face-down defense position to face-up attack position, all "Angel" monsters on the field gain 700 ATK points

Angel - Nostalgia

If this monster would be flipped face-down except by its own effect, you can keep it face-up instead to add 1 "Book of Moon" card from your Graveyard or from your Deck to your hand and pay 1000 Life Points. Then, flip this monster face-down

Angel - Righteous Fury

While the only monsters on your side of the field and in your Graveyard and LIGHT and/or DARK monsters, you may flip this monster face-down defense position once per turn, during your Main Phase. When this card would be flipped face-up Attack Position, except by Flip Summon, increase its attack by 300 and remove from play up to 1 monster on the field

Angel - Self-Made Justice

You may only Summon this monster if there exactly 3 LIGHT or DARK monsters in your Graveyard. Up to 3 times per turn, you may shuffle 1 LIGHT or 1 DARK monster in your Graveyard to your Deck to flip one face-up monster on the field to face-down defense position. After this effect has been used, flip this monster to face-down defense position

Angel - Sigil of Silver Light

Once per turn, during your Main Phase, you may have your opponent gain 500 Life Points to flip one of your monsters on the field from face-down Defense position to face-up Attack position or from face-up Attack position to face-down Defense position

Angel - Sword of Justice

This monster can attack once more during your turn for each monster that was flipped from face-up Attack Position to face-down Defense position during that turn

Angel - Tormented Soul

When this monster would be flipped from face-down Defense position to face-up Attack position, you can flip another monster on your side of the field from face-down Defense position to face-up Attack position, except "Angel - Tormented Soul"

Angel - Enlightened Mind

"Only via enlightenment can two opposing forces get together. Just like Ying and Yang work together, shall the Light prevail over all that means Darkness.. But it shall not eliminate it, but combine to create a deadly Alliance"

Synchros

Archangel - Gate of Darkness

1 "Angel" Tuner Monster + 1 or more non-Tuner DARK monsters
When this monster is Synchro Summoned, flip all monsters on the field to face-down defense position. Then choose and destroy 1 face-down monster on the field

Archangel - Gate of Light

1 Tuner Monster + 1 or more "Angel" non-Tuner LIGHT monsters
When this monster is Synchro Summoned, Flip all face-down monsters to face-up attack position (FLIP effects do not activate by the time). Choose and destroy spell or trap cards on the field up to the number of monsters that were flipped by this effect

Archangel - Gate of Heaven

1 "Angel" Tuner Monster + 1 or more non-Tuner "Angel" monsters
Once per turn, during your Main Phase, you can choose up to 2 monsters on the field and flip them face-down defense position if they are in Attack Position or flip them to face-up Attack Position if they are in face-down Defense Position

Spells

An Angel's Paradise

All "Angel" monsters on the field gain 300 ATK and DEF points. During a player's Draw Phase, if that player controls 3 or more face-down monsters, that player can draw an extra card

Angelic Reinforcement

Activate only while there is a face-down monster on your side of the field. Add an "Angel" monster from your Deck to your hand, remove a DARK monster from your Deck from play. Shuffle your Deck

Angelic Sacrifice

Send one "Angel" monster you control to the Graveyard to flip all Attack Position monsters your opponent controls to face-down Defense Position. Then, you may flip one monster you control from face-up attack position to face-down defense position or from face-down defense position to face-up attack position

Angels of Twilight

Whenever one monster would be flipped face-down or flipped to face-up attack position from face-down defense position, put 1 counter on this card for each monster flipped. You can remove 4 counters from this card to draw one card

Epiphany's Aegis

Flip all face-down monsters on your side of the field to face-up attack position (FLIP effects do not activate). Then destroy any non-"Angel" monsters on your side of the field and destroy X spell or trap cards on the field, where X is any number smaller than the number of monsters flipped face-up by this card's effect

Soft Embrace of Darkness

Tribute one face-down monster you control to destroy one face-up monster your opponent controls with an ATK power greater than the one of the tributed monster and draw 1 card

Tribute for the Archangels

Activate only by flipping one "Angel" monster you control to face-down Defense position. Discard one "Angel" card. Special Summon one "Angel" Tuner monster from your Deck or Graveyard and reduce its ATK and DEF values to 0. Remove it from play during the End Phase of this turn

Undying Soul

Pay 500 Life Points while you control a LIGHT attribute "Angel" monster to activate the following effect: Your opponent gains 1000 Life Points. Select one level 5 or lower "Angel" monster in your Graveyard and special summon it in face-down Defense Position

Vortex of Souls

Pay 100 Life Points during each of your Standby Phases. If you can not, this card is destroyed. Whenever one monster would be flipped from face-down defense position to face-up attack position, put 1 counter on this card for each monster flipped. You may remove 3 counters from this card to flip one monster from face-up attack position to face-down defense position or from face-down defense position to face-up attack position

Traps

Eyes of the Archangel

Flip one of your "Angel" monsters on the field to face-down defense position to flip one of your opponent's monsters to face-down defense position

Fallen Angel

Activate only when one of your "Angel" monsters is destroyed. Destroy one card on your opponent's field

Minerva - Angel of Fallen Truth

Activate only when one of your "Angel" monsters on the field is selected as an attack target. Negate the attack, end the battle phase, and Special Summon this card on the field as a Monster Card ("Angel-Minerva"/Fairy/Level 5/500 ATK/1200 DEF) (This card is still treated as a Trap Card). If it would be face-down while on the monster field, Set it back on your side of the field as a face-down Trap Card

Please let me know if you liked this set (or its idea, at the very least) and let me know what you think in terms of balance, as well