Franchise: Megami Tensei

In a 1992 developer interview, it was revealed that Cú Chulainn's name and design were inspired by Cú Chulainn from Yousei-ou manga series.

The attached image shows Shin Megami Tensei’s Cú Chulainn design (left) and its inspiration, the Cú Chulainn character from the Ryoki Yamagishi manga Yousei-ou (right).

The Persona games have many references to and take inspiration from the long-running manga series JoJo's Bizarre Adventure.

One example is in the third game, where the protagonists summon their personas using guns to shoot themselves. This is similar to the first scene of Stardust Crusaders, when Jotaro Kujo grabs a gun and shoots at his head in order to summon his Stand.

Another example is in Persona 4, when the main antagonist accidentally reveals himself by saying something he shouldn't have known. A similar situation happens in the fourth part of the manga, Diamond is Unbreakable.

"Phoenix Ranger Featherman R" is a fictional television series seen in most of the Persona games, having first appeared in Persona 2: Innocent Sin. It is a parody or homage to Tokusatsu programs like Super Sentai (Power Rangers in the United States) Most likely Chojin Sentai Jetman and Science Ninja Team Gatchaman.
In Persona 4 Golden all playable characters have costumes based on Phoenix Ranger Featherman R but only Chie and Yukiko are wearing females outfits while all the others are wearing male outfits.