Following HUMANITY FUCK YEAH! idea of humans being fucking awesome, I decided to create set of aliens that could show that humanity is badass while still posing a threat to mankind. I think that the best way is to do this like it happened on Earth. All of opponents will have an edge over humanity in one or two disciplines, but humanity will be one, all-around badass package. I wanted brand new aliens as I prefer custom stuff.
So lets start from dividing the humanity into 2 opposing factions, this is to make it clear that humans are individuals at first and always look to murder one another first. Both factions start the game at war with each other.
United Humanity (UH) - representing humans from Earth, created after yet another world war. Governed by rather oppressive regime led by Collective Consciousness (few leader's brains linked together). These are most normal humans in this setting. Expansionist, rather high numbers, totalitarian and untrustworthy.
Independent Space Colonies Armed Forces (ISCAF) - remnants of population that was, almost literally, nuked into space after last world war on earth. Due to low starting numbers they turned into bioengineering and robotisation. However bio and androids were given a lot of human traits and are part of society, yet humans are the one in charge. ISCAF also possesses the first "unbound" human, Dr. Carmen Waleraz, a person who exist completely separate from her body (Ghost in the Shell style). Remnants that left the earth consisted pretty much only from military personnel so ISCAF is pretty much only military, they look for any enemy weaknesses, always try to create some new instrument of murder. Militaristic, low population, very creative, high research, but low culture and diplomacy, prone to turtling.
Both factions are in state of mild-hot war, ISCAF put a huge distance between them and UH, to take time to rise an army capable of defeating UH. So now both factions know the other is out there and both are racing to create bigger guns then the other.
So this for humans, now to the main thing: the aliens. I dont have ideas for names, also I did get quite a few ideas from Mass Effect. Also only few ideas are more honed.
(some name) AKA. the Space Jellyfishes - pretty much Hannar from ME. Very peaceful as their bodies do not allow them to fight, however they are great diplomats, capable of creating huge alliances that can take down even biggest of threats. When at war they depend on mercenaries and allies. Otherwise they are pretty much space hippies. Peaceful, VERY weak military, but very strong diplomacy and high culture.
(some name) AKA. the robots, or Necrons - a "race" of robots. Long time ago some race decided to switch to robot bodies. Many ages later they are but shadow of former selves. Completely bound by logic they lack the "spark", our "Necrons" arent able to create anything, they only analyze. Because of this they are forced to pray on other civilizations and their techs. While they have big technological edge from the start they are VERY slow to progress in anything. Very aggressive, VERY low creativity, culture and research, strong military (they are fucking robots), LOTS of extra space on ships due to complete automation.
(some name) AKA. the Proud Warrior Race Guys - hailing from death world similar to Catachan, these guys are Warriors through and through. However they arent able to congregate because they are very prone to infighting. That is why they arent able to create any fleet that is bigger then ragtag bunch of ships belonging to one of the clans. They are similar to orks, but they cant tell "'ho's bigga" so they fight a lot among themselves. Very strong military, start on death world, penalty to fleet size, naturally discontent, rather large numbers.
Thats it for my more defined ideas, I still would need 5 more, so here are some basic ideas:
*some hive minded space bugs, huge numbers
*some religious freaks, culture bombing
*some faction with completely rigid social system, content population, but extremely inflexible
*some very short lived creatures that are permanently on sugar rush, huge research
*some Teladi-like space businessmen, powerful economy, low military (?)
So, we have divided humanity and some basic ideas for aliens that can pose a threat, but if humans put their mind into it they can kick every single one of them in the balls, unless aliens will ally themselves against them. Now how to expand this?