Summary
2401 Penitent Tangent is the monitor of Installation 05, referred to by the humans as "Delta" Halo. Although only shown briefly during the encounter with the Flood Gravemind deep in the bowels of Halo, 2401 Penitent Tangent is nearly identical to its brother monitor, 343 Guilty Spark, with the exception that it glows a dim red instead of bright blue. It speaks with the same upbeat, artifical voice that all Monitors appear to have, and expresses excitement at the sight of the Master Chief, because a Reclaimer can activate the facility and contain the Flood outbreak. A short argument with a semi-deceased High Prophet of Regret demonstrates that Penitent Tangent employs the same amount of regulation and protocol when it comes to dealing with the threat of the parasite. This is much to the dismay of Regret, who insists that "...of all the objects [the Forerunners] left behind, there are none so worthless as these [Monitors]!"
Also revealed by Penitent Tangent is the fact that the ring(s) have been activated exactly once before, and is/are quite capable of being activated again. It shouts at Regret for the Covenant's "blatant disregard of protocol" in controlling the Flood. Before anything more can be said, 2401 Penitent Tangent is taken away.
Even so, however, suggestions, and fans say that this, along with Guilty Spark, should play an important role when meeting even another monitor in Halo 3, if such a game will be created. Anyone who has played through Halo 2, and watched the cutscenes, saw that there were seven halos, and if the Bungie team makes another Halo game, there should be a time where all three monitors meet, to solve a very big problem. However, this is purely speculation.
Penitent Tangent also appears in the Multiplayer map 'Backwash', where he hovers around the air, occasionally talking quietly to himself. He serves no strategic or combat value whatsoever and will not acknowledge the presence of players.
Trivia
Also of interest is the fact that Penitent Tangent's number (2401) is 7 to the power of 4 whilst Guilty Spark's number (343) is 7 to the power of 3, as the number 7 is used frequently in Bungie games and mythology. Also, 2+4+0+1 = 7.
Also, one must note that there are seven unique letters in "Penitent Tangent".
In an earlier Bungie series, namely Marathon, names were often found to be sevens. A numerology grid was used as shown:
0 1 2 3 4 5 6 7 8 9
a b c d e f g h i j
k l m n o p q r s t
u v w x y z
Penitent Tangent is thus
P e n i t e n t
5+4+3+8+9+4+3+9=45, 4+5=9
T a n g e n t
9+0+3+6+4+3+9=34, 3+4=7
9+7=16, 1+6=7.
