As, arguably, the most well-known character on this list, Galactus really needs no introduction. That said, he is the planet-devouring force of nature who needs to consume worlds in order to provide his body with the energy it needs to live - and he needs to live in order to maintain the universe's balance, as he is an essential aspect of its very existence. He possesses the virtually limitless energies of the power cosmic and, as such, has a very esoteric array of powers. He can manipulate matter and energy, erect nearly impenetrable fields, project extremely potent energy blasts that are powerful enough to destroy planets, open wormholes or portals to other dimensions and time, transport beings across the universe and across time, teleport, read minds, use telekinesis, reconstruct matter or transmute it (such as turning water into ice), turn matter into energy or vice versa, erase memories through manipulating souls, repair or heal living tissue and even resurrect the dead. He also uses advanced alien technology to augment these powers. He can appoint lesser beings as his "Heralds" (servants who seek out suitable planets for him to dine on) and they include characters like the Silver Surfer, Terrax, Firelord, Air-Walker, Stardust, the Fallen One and Red Shift. Even after having been granted a mere fraction of Galactus' power, these guys can destroy planets with their energy blasts and survive in the harsh conditions of a black hole. Galactus is so abstract that he can't be perceived in his true form. Different civilisations view him in different ways, which is why humans see him as a giant human being in a purple helmet (he can also manipulate his own size so that he can communicate on our level).
15. The In-Betweener
The In-Betweener actually represents duality itself. Therefore, he weirdly represents opposing concepts such as good and evil, reason and emotion, truth and illusion and life and death (we know, it makes no sense whatsoever). His "contrasting-halves" appearance shows us this in an aesthetic way. He is also an agent of the conceptual beings Lord Chaos and Master Order (we'll get to them later), but it is entirely up to him which side of the fence his loyalty lies in that regard. He is able to manipulate cosmic energy in order to alter reality to achieve nearly any effect or ability within his influence as the synthesis of duality, while another major ability is being able to analyse a target and direct energy towards it in a "polar opposite" form, which is instantly fatal to said target. That said, his coolest ability is undoubtedly that he can directly summon an enemy's opposite being, if he cannot synthesise the "opposing energy" necessary to eliminate them himself, and eliminate them that way (for example he could summon a being of darkness to eliminate a being of light etc).
