Intergalactic Travel

The ability to travel across galaxies was first developed by the Soli, then the Tolana. The Soli and Tolana live in the same galaxy, the Circinus Galaxy. Both have a long history of interstellar travel within the galaxy. The Tolana, in the last few hundred years, have used interstellar travel to dominate most of the Circinus galaxy, while the Soli have maintained their independence by developing advanced biological weapons.
  The Soli have used intergalactic travel for research, exploration, and the testing of technology. They discovered Earth and Mars before the Tolana. They debated on the ethics of helping either planet, and, deciding that interference would be too disruptive to evolution, they left without making contact. This decision was driven by guilt from interfering in the Rhonian rebellion, leaving damaging consequences to the Rhonaians. Several Solis scientists, however, disagreed with the decision to leave the Milky Way without contact, especially those that saw the projection of the Tolana invasion.
The Tolana developed intergalactic travel via warp bubbles and exotic matter. By the time they crossed into the Milky Way and invaded Earth, Earth had functional and constantly evolving interstellar travel, making weekly trips from Earth to Mars. Earthlings had begun preliminary development of intergalactic travel, using the Alcubierre theory of warp bubbles, similar to Tolana design. While the Earthlings were behind on the technology, the Tolana saw potential in both building a growing military presence but, more importantly, a cheap labor supply for their continued growth of Mech weapons, suits, and robots. While much of the work initial building of mech was automated, they needed they land to build the factories, and a core of workers who could repair damaged battle mechs. They also saw Earth as a potential for building a subservient population, after the loss of the Rhonians as their main labor force.