Sub-Mariner Vol.1 #22
Returning home to Atlantis, Namor has his ability to breathe underwater restored to him by Ikthon. During the process he is contacted by Dr. Strange telepathically, who asks for his aid in stopping the Undying Ones, demons from another dimension who centuries ago once ruled over man, until man defeated them.
Printed: Feb 1970
Writers: Roy Thomas
Art: Marie Severin and Johnny Craig
Cover: Marie Severin