"The Dark Circle" is a nine-page complete Shinobi story published in The Official Sonic the Hedgehog Yearbooks. While the circumstances in which Shinobi crossed publications are not yet clear, in sharing the same setting and characters - and creative staff - as its later incarnation in Sonic the Comic, "The Dark Circle" can be considered a prequel to "The Fear Pavilion".
- All stories in the Yearbooks are uncredited, but Jon Haward and his brother Jim Haward directly signed their artwork to establish their contribution to it.
Night in Tokyo, and under cover of darkness the modern-day ninja Joe Musashi continues his pursuit of the Neo Zeed. Following a lead to an industrial estate in the city, he confirms the presence of a Neo Zeed holding through the Japanese character for "Void" - the codename of the Neo Zeed's anonymous leader - inscribed by a door. Blasting through the door with plastic explosive - Joe is a ninja who has moved with the times - Joe begins investigating the building.
The location initially seems deserted and derelict, and Joe's regular haregai scans - a ninja-trained 'sixth sense' technique - apparently confirms that no-one else is present. Joe emerges from the back rooms of the building into a brightly-lit and opulently-furnished foyer, but despite these grand fittings naturally indicating a place of value and interest Joe's haregai continues to assure him that he is the only person in the vicinity. Perturbed but trusting to his senses - which are highly-attuned as only a ninja's can be - Joe ascends to a mezzanine level, musing on rumours that the Neo Zeed's ninjitsu has become so advanced that it has transformed into literal magic. Joe considers such notions to be overwrought fantasy... but he has cause to consider them more carefully when smoke suddenly erupts around him and an assailant strikes him in the back of the head!
The attacker is skilled, knowing where to hit to inflict a disabling blow, and it is only thanks to his finely-honed physique and stamina that Joe is not knocked out. He struggles to defend himself, but the thick smoke drowning the room effectively blinds him, and for some reason Joe's haregai has failed him - he cannot sense the attacker at all, and Joe continues to be sent reeling by the relentless assault.
Repeated blows to the head leave Joe groggy, and it takes the supreme concentration of all of his effort to avoid passing out. Joe manages to clear his vision by feeling about for a window and smashing it, draining the smoke obscuring the room. Even though he can now see, Joe is surprised by the attacker - now revealed to be a Neo Zeed ninja - one more time, as the haregai once more doesn't alert him to the fact that the ninja is hanging from the ceiling above him.
Joe is battered and bruised from his one-sided engagement, but now that the Neo Zeed ninja has exposed himself the playing field has been levelled. Joe's greater aptitude in ninjitsu comes to the fore in direct battle, and despite his injuries he knocks out his opponent. Even though his downed opponent is helpless, Joe spares his life, reiterating his resolution to never kill an enemy and bring himself down to the level of the criminal Neo Zeed.
In the end, this operation leaves Joe no closer to finding his beloved Naoko, but despite that it has not been a wasted venture, as Joe has learned both valuable intelligence about the Neo Zeed's ninjitsu - now sophisticated enough to have developed methods to confound his haregai and ninja sense - and about himself. Joe realises that he cannot overly rely on special powers, and that a balanced approach - combined with unerring determination and resolve to withstand pain and setbacks - will bring him victory in his quest.
- Joe Musashi wears his 'first-generation' costume in this adventure, which he also uses in "The Fear Pavilion". In subsequent stories he would substitute the outfit worn in the videogame The Revenge of Shinobi for his ninja gear.
- The Neo Zeed clan member in this story wears a black uniform. In later stories this would be changed to purple livery.
- Musashi's "ninja radar" is referred to as haregai in this story. In future Shinobi stories, the spelling is changed to haragei.
Within the context of the Yearbooks this story is a standalone oneshot, but The Fear Pavilion can be considered a follow-up to it.