Mistress Death has seen the Entities and their plans to escape her DEATH itself, so she has decided to intervene by adding a little bit extra to your conversion process into an Eternal, gifting you the complete legacy of the Mad Titan Thanos from Universe 616 without causing any changes you do not want to your mind & soul.
This legacy gives you the bionic amplification and mystical enhancement that Thanos did to himself, and Mistress Death did when she resurrected him as her Avatar. These enhancements have increased your strength beyond the original limits of even the strongest Eternals. You will be able to fight Worthy Thor, who is using the Power Gem, defeat the likes of the Silver Surfer, and physically subdue an Angry Hulk with ease. All of this can still be enhanced with cosmic energy when needed.
Your durability is now nigh-invulnerable, such that even a point-blank, planet-destroying hit from Power Gem-wielding Thor leaves only a bloody nose, or three full screams from Black Bolt, leaving no significant damage aside from damaging your clothes. While blasts from Odin and Galactus leave you wounded but coming back for more. You can survive the extreme environment of a 2-light-year-wide black hole and only be covered in light wounds.
Your energy projection abilities are now at the level where your blasts are capable of knocking down the likes of the Hulk and Thor, and are even able to graze Galactus's armor as well as blast someone of his level off his feet and send him across the moon.
Your mind is all but invulnerable to most forms of psychic attack, to the level of the Mind Gem in power. Even people as skilled as Moondragon or Mantis wouldn't be able to break your defenses. Your skill with the Mind is so great that you can mess with minds on the level of Reed Richards'. These powers, combined with Thanos's great charisma, have allowed him to turn even hated foes to his side temporarily. You also have access to his most dangerous technique, the Time-Mind Sync Warp, a move that plunges the victim's mind into a psychedelic dimension of insanity, causing death or incapacitation.
The greatest part of this legacy is Thanos's intelligence and knowledge, which makes Thanos one of the most dangerous beings in the Multiverse. Thanos is a genius in virtually all known fields of advanced science and has created technology far exceeding contemporary Earth science created by Tony Stark, Bruce Banner, and Reed Richards. Considering such people smart for a human but children to someone like him. As well as being one of the greatest fighters in the universe.
You can summon Thanos's Space Throne, a throne linked to you through techno-magic. It is capable of faster-than-light travel, teleportation, and dimension travel. The Throne was also capable of working as a focus for your power to generate powerful force fields and energy blasts.
As an Avatar of Death, you can bring Death to that which cannot Die, and with Thanos's skill with Magic and his and your status as an avatar of Death, your understanding of Death and Necromancy are raised to the highest possible.
Until you defeat the Entities, you are banned from Death itself, rendering you truly immortal. You can still die, but you will always return, no matter the severity of any injury.