CT-27-5555, also known as ARC-5555 and
later re-designated as CT-5555, was a clone
trooper who served in the Grand Army of
the Republic during the Clone Wars.
Because of his clone designation, he was
given the nickname "Fives." Around 22 BBY,
right about the time that the clone war had
begun, Fives was assigned to Domino
Squad, a unit of clone cadets that trained
within the planet Kamino's Tipoca City
military complex, under the command of
the Siniteen Sergeant Bric. Fives and his
squad were required to pass a test in order
to become battle-ready clone troopers.
After the completion of their training, Fives,
along with a number of other rookie clone
troopers, was assigned to Rishi Station, a
listening post located on the moon of Rishi.
Fives was present when the Confederate
General Grievous invaded the moon to take
control of the Republic listening post. With
the arrival of Clone Commander Cody and
Clone Captain Rex, the two clone officers
helped Fives and the surviving rookie
troops retake the outpost.

Fives and trooper Echo, the only rookie
survivors of the battle, were rewarded with
medals for their service on the Rishi moon
and were inducted into the 501st Legion.
They later helped defend Kamino after
Grievous, along with Dark Acolyte Asajj
Ventress, invaded the planet and attacked
Tipoca City. Following the Confederate
attack on Kamino, Fives and Echo were
promoted to ARC troopers for their
continuous efforts. As the war continued,
both Fives and Echo joined Jedi Generals
Obi-Wan Kenobi and Anakin Skywalker in
the rescue of Jedi Master Even Piell from
the Confederate prison known as the
Citadel. After they rescued Piell and his
officers, the facility's warden, Osi Sobeck,
released battle droid forces on Fives and
the Republic group. While Echo and Piell
perished during the battle, Fives and the
surviving members of his team were
rescued by Jedi Master Plo Koon.

Some time later, Fives was assigned on
special assignments to the 501st legion
during the attack on Umbara. When
General Pong Krell took over command
from Anakin Skywalker, Fives was the
loudest voice against Krell and his
leadership. Fives was later proven correct
when Krell revealed himself to be working
against the Republic.

Fives was also present during the Battle for
Ringo Vinda. When Tup went crazy and
assassinated General Tiplar, Fives took him
back to Kamino for further medical study.
Fives found surprising evidence that
contradicted what the Kaminoan scientist,
Nala Se had found, which led him to
conduct a full study and research on his
own, hiding from Republic authorities.
When Shaak Ti ordered him to present his
evidence to the Chancellor, Nala Se
drugged him and Palpatine faked an
assassination attempt. On the run, Fives
tried to convey his information to General
Skywalker and Captain Rex. However, he
was tracked by Commander Fox and a
group of Shock Troopers. When Fives tried
to defend himself, Fox shot him through the
heart. Fives died knowing the truth about
Chancellor Palpatine and Order 66, but was
unable to communicate this to anyone
before it was too late.