With a release date set for 2018, the buzz surrounding the Infinity War is slowly building up. Even if there isn't much known about this particular flick, we can all expect that Thanos will reveal his endgame and show us why he is the most feared villain of the Marvel Cinematic Universe.
The Russos have teased this project in numerous ways until now, most lately having said that the Defenders are being taken into consideration for a cameo. Josh Brolin is already on the set of the Infinity War, and everything seems to be going according to plan. As it always happens with the MCU, for that matter.
The most recent (and unconfirmed, just yet) reports suggest that the Infinity War movie will feature a character who was essential in the comic book storyline. And this character is none other than Death herself. Since the character wasn't cast just yet, the rumor says that she will be adapted for the big screen. Which makes sense, since the MCU hasn't presented any cosmic entities from the comics so far.
Thus, Screen Rant (citing LRM) says that the MCU version of Death will be none other than Hela, who is set to appear in Thor: Ragnarok for the first time. Since the destruction of Asgard is imminent, this rumor does fall in line with what is about to happen.
And since Cate Blanchett is one of the most well-known actresses in Hollywood, it makes sense to have her around for more than a single movie. Revealing in Thor: Ragnarok that she is in fact the embodiment of Death would be no surprise to many. On the other hand, this would risk confusing the general audiences, who might be left wondering about the difference between the ruler of Hel and Death itself.
As said, this is just a rumor. However, it should be taken into consideration, especially since we don't know why the Mad Titan is searching for the Infinity Stones.
