And here's their in-universe explanation:
Since the first known encounters with them, xenobiologists have supported theories suggesting that Tholians are far more different from other forms of intelligent life than even their strange outer appearances suggest. One of the cornerstones of these theories is the notion that the Tholian Assembly actually spans multiple dimensions in spacetime. These claims are supported by their frequent involvement with the so-called “Mirror Universe,” as well as their apparent interest in the Temporal Cold War, and time displaced artifacts. It is said that the Tholian homeworld inhabits a region of space where the borders between dimensions are unnaturally thin, and that they have developed technology that allows them to cross those borders at will.As ever a perfect balance of Federation and Klingon goodies ahve been introduced, including the Federation Wells class, and a sleek new Klingon equivilent, as well as mirror universe variants of both, shuttles, and other new mirror universe ships. Here's the lowdown:
Up until now, these leading theories have been unsupported by much in the way of facts, as infiltrating the Tholian Assembly proved to be an impossible task. Recent evidence of Tholian activity within the Nukara System and the Azure Nebula has put nearly all remaining doubts to rest.
Within these areas, Tholian operatives have been utilizing multi-dimensional phasing technology to not only penetrate the borders between our spatial dimensions, but also the barriers of the space-time continuum itself. Their temporal incursions have resulted in the retrieval of technology, weapons, personnel and even entire starships, pulled from distant times and places.
Their temporal incursion technology is not perfect, however. Ripples from their activity have caused uncontrolled temporal anomalies to appear up to several hundred light years from their source. Daredevil profiteers from the Lobi Crystal Consortium have set up an intricate supply chain dedicated to seeking out these uncontrolled ripple anomalies, and exploiting them to retrieve goods that they can then sell to the highest bidders. Both Starfleet and the Klingon Defense Force have an obvious interest in these valuable time-displaced artifacts, for it may be that the fate of time itself will be in the hands of the faction that controls them.
Among the ships that have been recovered were Wells Class Temporal Science Vessels. These appear to be the same class as the Federation Timeship encountered by Captain Kathryn Janeway in 2375 (so to speak). As Janeway described in a classified debriefing, "The U.S.S. Relativity's mission was to protect the timeline from temporal incursions." The Federation's interest in these vessels cannot be understated.
The Wells Class Temporal Science Vessel comes with a Tipler Cylinder Universal console module. The Tipler Cylinder can actually rewind time! The dense beryllium cylinder core of this module rotates at near light speed, allowing your ship to perform a Temporal Backstep and rewind time approximately 13 seconds. Your ship's position reverses, and some of your ship's hull and shield damage is restored. Additionally, the cooldown and recharge times on all your abilities are reset.
The Tipler Cylinder is part of a set, and can be used on any Timeship, including the Wells, Mobius, Korath, Krenn, Aeon or Rozhenko class vessels. If you also have a Manheim Device equipped, activating the Temporal Backstep will also cause all nearby foes to freeze in time until the sequence has ended.
Mobius Class Temporal Destroyers appear to be similar to the Federation Timeship encountered by Captain Kathryn Janeway. Unlike the Wells Class, however, these ships appear to be from the Mirror Universe, and as mirror universe ships, it is not surprising they seem to be built more for combat, than for protecting the timeline.
The Mobius Class Temporal Destroyer comes with a Manheim Device Universal console module. This console is based on Dr. Paul Manheim's time-gravity work in the early and mid-24th century. His experiments caused ripples in time, now called the Manheim Effect. The Manheim Device console can create quantum duplicates of yourself — one from your past and one from your future.
The Aeon Timeships appear to be the same class as the Federation Timeship encountered by Captain Kathryn Janeway in 2373. The U.S.S. Voyager's encounter with one of these small crafts left them stranded in 1996. That same craft crashed in the High Sierras in 1967, where it was discovered by Henry Starling, who used the technology on the ship to drive Earth’s advancement in computers all through the late 20th century. The Federation's interest in these vessels cannot be understated.
The Aeon Timeships come with a Subatomic Deflector Array. This Deflector provides a small improvement to Starship Flow Capacitors, Particle Generators, Shield Systems and Shield Emitters. The Deflector also enables you to fire a Subatomic Disruptor. This devastating weapon fires a single massive sustained beam capable of breaking apart a target's molecular structure. It can be equipped on any small craft.
Similar to the Federation Wells Class, the Korath Class Temporal Science Vessel comes with a Tipler Cylinder Universal console module.
The Krenn Class Temporal Destroyers are not only from the future, but they also appear to be from the Mirror Universe. They are very similar to the Korath Temporal Science Vessels, however, as a mirror universe ship, it is built more for combat.
Presumably named after Alexander Rozhenko, Son of Worf, who has recently funded research into temporal mechanics, the Rozhenko Timeships is a small craft with fantastic power. The Rozhenko Timeships come with a Subatomic Deflector Array.
Mirror universe ships
Federation players will find either a Mirror Universe Deep Space Science Vessel or Mirror Universe Reconnaissance Science Vessel, while KDF players will find a unique Qin Raptor variant dressed in a Mirror Universe skin. As an additional feature coming along with this round of Mirror Universe vessels, we have also enabled the use of the I.S.S. registry prefix for these (or A.K.S. for Klingon equivalents) and all previously available Mirror Universe ships. These prefix unlocks will only be usable on Mirror Universe ships.
To go with all the ships there are also new timeship bridges:
And new uniforms:
There are also new logos for the DTI and Klingon equivilent.
You can see a larger version of the DTI one on Thomas Marrone's blog. And you can see more images of all those ships here, and here.