Timelord

"Timelord", known as "Time Machine God" (, Jikaishin) in Japan, is an archetype of Fairy-Type Monster Cards used by Z-one. In the OCG, the archetype is exclusively supported by Boss Duel cards.

According to Z-one, there are 10 of them, in which he refers to them as aspects to the Almighty God, the eleventh member ("Sephylon, the Ultimate Timelord").

"Necrolancer the Timelord" is not a "Timelord" card, because it does not have 「」 in its Japanese name.

Origin
The first 10 "Timelords" are based on the 10 attributes or emanations of the Tree of Life (also known as the Sephirot), the mystic symbol used in Kabbalah, with "Sephylon, the Ultimate Timelord" being named after the Sephirot itself. The "Timelords" are all depicted as machines with screens on their chest that shows a face, which accordingly are the faces of angels. The bodies are then metal suits of armor being manipulated by the angel whose face it contains.

Each of the "Timelords" reflect a part of the Sephirot, as well as one of the archangels (except "Sephylon", who is based on the mystical state Da'at, the divine light, where all Sephirot become one).

Members
The "Timelords" are Level 10 Fairy-Type monsters of various Attributes, except DARK. The majority have 0 ATK and 0 DEF, except for the last two ("Sandaion" and "Sephylon").

The first 10 "Timelords" (excluding "Sephylon") all share the following effects:
 * "Cannot be Special Summoned from the Deck. If you control no monsters, you can Normal Summon this card without Tributing. Cannot be destroyed by battle or card effects. You take no battle damage from attacks involving this [Attack Position] card. [...] During your Standby Phase: Shuffle this card into the Deck."

In Yu-Gi-Oh! 5D's Tag Force 6, the first 10 "Timelords" only provide battle damage immunity while they are in Attack Position; in the OCG/TCG, this limitation only applies to "Metaion", the first one.

In the anime, the shared effects are instead:
 * "Negate this card's destruction by battle or by card effects. You can reduce any Battle Damage a player takes from battles involving this face-up Attack Position card to 0. [...] While you control this face-up card, you cannot Summon monsters. During your Standby Phase, return this card to the Deck.

In addition to the above, each of the first 10 "Timelords" has a unique effect of their own. This effect activates at the end of the Battle Phase in which they battle (except for "Raphion", whose effect activates at the end of the Damage Step); in the anime, the effect instead activates right after they battle. These effects all involve returning cards back to the hand or Deck, raising the player's LP, and/or lowering the opponent's LP (aesthetically, the cards and the player's LP are "sent back in time" to where they used to be, or the opponent's LP may be "sent forward in time"). "Lazion" and "Zaphion" (the latter anime only) also have an additional effect outside of the Battle Phase. When the "Timelords" were first made playable in the video game Yu-Gi-Oh! 5D's Tag Force 6, many of these unique effects were toned down; some effects were further changed when released in the OCG/TCG.

A full list of unique effects follows:


 * "Metaion" returns all other monsters on the field to the hand, and inflicts 300 damage to the opponent for each monster. In the anime, it returns only the opponent's monsters instead of all other monsters.
 * "Lazion" shuffles all cards in the opponent's Graveyard back into the Deck. In addition, it inflicts 1000 damage to the opponent if they draw a card(s), once per turn. (In Tag Force 6, this damage is reduced to 500 but does not have a once per turn limit. In the anime, it shuffles into the Deck all monsters the opponent controls, in addition to all cards in the opponent's Graveyard, and inflicts 1000 damage whenever they draw, but only during the Draw Phase.)
 * "Zaphion" shuffles all Spell and Trap Cards the opponent controls back into the Deck. In addition, it allows it's controller to draw 1 card when it was sent from the field to the Graveyard (In Tag Force 6, it does not have the additional effect of allowing its controller to draw card. In the anime, it allows its controller to draw until they had 5 cards in their hand when it leaves the field, including if it is returned to the Main Deck.)
 * "Sadion" makes its controller's LP become 4000, if their LP is lower than 4000.
 * "Kamion" shuffles 1 card the opponent controls into the Deck, and inflicts 500 damage. Neither player can activate cards or effects in response to this effect's activation. (In Tag Force 6, it only shuffles monster and does not restrict players from activating in response. In the anime, it shuffles all monsters the opponent controls into the Deck, then inflicts 500 damage for each one.)
 * "Michion" halves the opponent's LP. (In the anime, it inflicts effect damage to the opponent equal to half their LP.)
 * "Hailon" inflicts damage to your opponent equal to the difference between your and the opponent's LP, but only if your LP is currently lower than the opponent's. (In the anime, it activates regardless of whose LP is higher.)
 * "Raphion" inflicts damage to the opponent equal to the ATK of the monster it battled. (In the anime, it returns that monster to the hand, and if it does, it inflicts the damage.)
 * "Gabrion" targets 1 card the opponent controls and shuffles it into the Deck. (In the anime, it shuffles all cards the opponent controls into the Deck.)
 * "Sandaion" inflicts 2000 effect damage to the opponent. Additionally, although it has 4000 ATK, the opponent takes no battle damage from attacks involving it. (In the anime, it inflicts 4000 effect damage and is able to inflict battle damage.)

"Sephylon" is in a class of its own, having none of the effects of the first 10 "Timelords". Unlike the other "Timelords", it cannot be Normal Summoned/Set, but can be Special Summoned by having any 10 or more monsters in the Graveyard. Once per turn, it can Special Summon 1 Level 8 or higher Fairy-Type monster from the hand or Graveyard and make its ATK become 4000, but it has its effects negated.

In the anime, "Sephylon" could only be Special Summoned through "Infinite Light", but does not have a Normal Summoning restriction. Each turn, it can Special Summon as many of the other "Timelords" as possible back from the hand, Deck, or Graveyard, and make the ATK of all those monsters become 4000. Furthermore, it gains ATK equal to the combined ATK of all other "Timelords" you control, any monster it battles has its effects negated, and it can protect itself from destruction and battle damage by banishing another "Timelord" monster you control.

So far, the "Timelords" released in the OCG and TCG are "Metaion" and "Sephylon", with "Lazion", "Zaphion", "Sadion" and "Kamion" set to release in the OCG in Collectors Pack 2017. A number of Tokens have also been shown off as Boss Duel exclusives.

Weaknesses
While the "Timelords" cannot be destroyed, they are not invincible, and can still be removed from the field by other means, such as by being banished or Tributed. It is also possible to remove them from the field by returning them to the hand or Deck, although returning them to the hand is less useful since they can simply be Summoned again next turn. In either case, cards that protect against direct attacks are useful for overcoming this weakness.

In addition, cards that can negate a "Timelord's" effects are extremely useful, as that will strip them of all their protection, generally leaving the opponent with a 0 ATK monster that cannot do anything. (However, this will be less useful against "Sandaion" and "Sephylon".)

Since all "Timelords" are Level 10, cards like "Level Limit - Area B" and "Gravity Bind" can easily prevent them from attacking and being able to use their powerful effects. Since it is very difficult to control more than 1 "Timelord", cards like "Scrap-Iron Scarecrow" and "Hook the Hidden Knight" are also very effective at stopping their attacks.

Cards that can attack the opponent directly, such as "Earthbound Immortal" or "Toon" monsters can be very useful against "Timelords", as they can bypass their protection and effects and deal your opponent significant damage in the process.

"Timelords" rely on attacking for their effects to go off, so any number of basic stall cards that aim to block the opponent's attacks will stop them as well. However, their effects also go off when they are attacked, so cards that force an opponent to attack them will still trigger the "Timelords" effects.

Trivia

 * In the anime, all the Timelords have a Rare rarity with exception of "Sephylon", which has an Ultra Rare rarity instead.
 * Time Lords are of a race of time-manipulators from the series Doctor Who.
 * "Sephylon, the Ultimate Timelord" was originally named "Sephylon, the Ultimate Time Lord", but this was later changed to "Timelord", likely to maintain consistency with the other "Timelord" monsters.