Issue(s): Avengers #52
Published Date: May 68
Title: "Death calls for the arch-heroes!"
Credits:
Roy Thomas - Writer
John Buscema - Penciler
Vincent Colleta - Inker

Review/plot:
The Black Panther arrives at the Avengers Mansion and decides to sneak in. I read these issues with Christopher Priest's retcon that the Panther joined the Avengers basically to assess their threat level in mind, and so far it works. He arrives inside to find Goliath, Wasp, and Hawkeye apparently dead.

Jasper Sitwell walks in on the scene and assumes that the Panther is responsible, and has him arrested.

It turns out that the Avengers were only put in a death-like stasis by the Grim Reaper, who is out for revenge for his brother, Wonder Man, and the Panther helps them revive and defeat him.

The Reaper wears the most garish costume imaginable: green and purple and blue and orange.

Throughout this issue the Black Panther is referred to as just "Panther", and his face mask is half open; i suspect this is so that we can see that he is black.

As Shar notes, cameo by an out of costume Black Widow...

...and also brief scenes of the Big Three inactive Avengers reacting to the "death" of the current team.

Quality Rating: C

Historical Significance Rating: 8 - first Grim Reaper. Black Panther joins the Avengers.

Chronological Placement Considerations: Hearing about their death, Tony Stark thinks to himself that he just saw the Avengers "only days ago" and decides to investigate after he finishes working on his test robot. Captain America just returned from battling the Sleeper. Thor is just hanging out, reading a newspaper. None are seen again this issue.

References:

• The Avengers fought Wonder Man in Avengers #9.

Cross-over: N/A

Continuity Implant? N

Reprinted In: Marvel Triple Action #44

I don't think the Grim Reaper ever wears this costume again.

Natasha appears in this issue, too (she'd given up her costumed Widow identity in #45 but resumes it in #57).

Added her as character appearing (and added a few more scans to this post as well). Thanks!