By far the strongest and most powerful Titanian Eternal, Thanos is a superhuman mutant whose massive, heavy-bodied form was born with the capacity to synthesize cosmic energy for certain personal uses. Thanos has increased his powers through bionic amplification, mystical enhancement, and as a result of being resurrected by Death itself.
Possibly Thanos' most dangerous ability is his mind. Thanos' intellect is dedicated to enhancing his own powers and to the annihilation of all life. Thanos is a genius in virtually all known fields of advanced science and has created technology far exceeding contemporary Earth science.
Thanos possesses vast superhuman strength the full limits of which aren't known. Death has increased his strength beyond their original limits to levels rivaling or surpassing those of the physically strongest Eternals. Thanos is one of the strongest beings in the Universe and is capable of lifting far in excess of 100 tons without any effort. Thanos' strength is so vast he has destroyed entire planets with the simple force of his blows. He has proven capable of fighting both Thor and the Thing simultaneously for an extended period. His strength reserves are so vast that with only a handful of blows, he has been able to beat the likes of the Silver Surfer to the brink of death. Thanos can augment his strength with his cosmic energy when needed.
Despite his massive muscular bulk, Thanos is capable of running and moving at speeds greater than the finest human athlete.
Thanos' musculature produces almost no fatigue toxins during physical activity. As a result, he has limitless superhuman stamina in all physical activities.
Before his "death", Thanos possessed an impressive degree of resistance to physical injury, even compared to other Eternals. After his resurrection, Death increased his ability to resist injury to a much greater degree and he is nigh invulnerable. He has withstood at point blank range planet destroying attacks without any harm. He has withstood blows and attacks from beings as powerful as the Silver Surfer, and even Thor unharmed. He possesses such an incredible resistance to injury, he has been shown to survive point blank blasts from universal level entities such as Odin and Galactus.
Thanos, like all Eternals, is immortal in the sense that he is immune to all known diseases and infections and is immune to the effects of aging. Thanos was formely banned by Death itself from entering its realm, rendering him truly immortal. No matter the severity of any injury, Thanos was unable to die and completely recovered. This ban has since been lifted.
Regenerative Accelerated Healing Factor
Despite his extraordinary durability, it is possible to injure Thanos. Like all Eternals, however, Thanos is capable of regenerating damaged tissue with much greater speed and efficiency than a human being. His healing powers aren't as developed as those of some Eternals. Some Eternals are capable of regenerating any destroyed tissue. Given the circumstances of his latest death, Thanos is unable to regenerate missing organs.
Despite his great size, Thanos' agility, balance, and bodily coordination are enhanced to levels that are beyond the natural physical limits of the finest human athlete. His agility is roughly equal to that of the average Eternal.
Thanos' reaction time is enhanced to a level that is beyond the natural physical limits of the finest human athlete. Like his agility, his reflexes are about average for an Eternal.
Energy Manipulation Control
Thanos has displayed great versatility in the use of his energy projection abilities. He has demonstrated the ability to project pure energy as a concussive force, gamma radiation bursts,"magnetic" energy(Avengers Annual#7(1977) page 42 panel 1--energy from his hand towing the Star-Gem), infrared heat-beams from his eyes, and disruptor beams, as well as form vastly powerful energy shields, barriers, and force-fields. It is also very likely that Thanos is very capable of flight and levitation by negating the force of gravity on his body as well as fly in space at faster-than-light speeds but Thanos very rarely if ever does so. The exact extent of Thanos' energy projection abilities are unknown, but a single eye-blast has been capable of rendering the Thing unconscious and knocking down the likes of Thor. His blasts are so strong and powerful he has been able to easily destroy planets and release In-Betweener from his prison created by Master Order and Lord Chaos. It has been speculated that the nature of Thanos' cosmic energy reserve may be quasi-mystical in nature.
Thanos possesses vast psionic abilities. His mind is invulnerable to most forms of psychic attack. So far Thanos has demonstrated the ability to project blasts of psionic energy, as well as being able to shut down another being's mind and can communicate telepathically with most if not all beings.
Matter Manipulation & Control
Thanos has demonstrated the ability to manipulate matter on the atomic level similar to other Earthborn Eternals. On one occasion, he turned the Skrull, Skragg into stone.
Thanos can teleport himself across unknown distances under his own power in the same manner that most Earthborn Eternals can. It is likely that Thanos, like most Earthborn Eternals find the process unpleasant and instead, prefers to use teleportation technology.
Although he typically avoids physical combat, Thanos is a highly formidable hand to hand combatant. He is particularly skillful at using a combination of his physical and energy manipulative abilities during combat. He also has great knowledge of arcane and mystical lore.