Shun first appears while Koga fights Miguel, and sends the Silver Saint away. Telling Koga the story about how the Cloths changed shape and received the power of the elements during their battle against Mars, he tells the young Pegasus how he received the Darkness Wound while defending Athena. Miguel attacks again, having heard Shun's story. Shun, willing to sacrifice himself to save Koga and Ryuho from the Silver Saint, burns his Cosmo and uses the Nebula Chain, wounding Miguel, before Koga and Ryuho defeat him together. Shun entrusts the future to the new generation of Saints, watching as they resume their journey.
Shun is seen again as he tries to defend two brothers from Halimede, but is fooled by the Pallasite's fake surrender, and fails to protect the oldest brother name Phillip, receiving great hate from the little boy known as Rei. Shun meets Ryuho, Souma and Yuna, telling them about his brother Ikki and that neither he, Seiya, Hyoga or Shiryu knew about Ikki's whereabouts. Halimede attacks again, and Shun fights back without his Cloth as Rei took it in hope of getting his brother back. However, Rei attacks Halimede later and gets the Clothstone, and it changes shape, becoming Shun's new Andromeda Cloth. With it, he easily defeats Halimede before continuing to defend the village.
Invasion of Pallasvelda
Shun arrives along with Hyoga and Shiryu, to help the other Saints in the battle against the Pallasites. He joins forces with Koga, Souma and Yuna when the Saints split up into groups of four.
They would face the Class 2-Pallasite Surtr, and Shun would arrive a little bit later after having dealt with all the footsoldiers behind them. However, even the Legendary Andromeda struggled against the Pallasite before learning of his weakness, defending Koga as he broke through the barrier and crushed the Mystic Stone. Now without the barrier, Shun finished the Pallasite with his Nebula Storm.
Later, they would face the Class 1-Pallasite Aegaeon. No matter what he did, Shun could not defeat the Pallasite, and he was severely wounded. As they all got up once more, Aegaeon was about to fight for real and kill them. However, Ikki arrived to defend his younger brother once more, and sent them ahead while he took over the battle. After the battle against Aegaeon was over, Shun was devastated as a phoenix feather flew into Shun's hands, then disappeared, indicating Ikki's death. Shun quickly overcame his brother's death and kept fighting alongside his fellow Saints.
Shun's Cosmo has increased significantly during his time as one of Athena's Saints, although he still struggles against stronger opponents due to holding back his strength as when he fought Surtr. Even if only for a short time, Shun was able to hold his own against Aegaeon, one of the Four Heavenly Kings protecting Saturn.
In several flashbacks and in the second season of Omega, Shun is seen wearing the Omega version of his Andromeda Bronze Cloth from the Hades Arc, adding more protection to the upper arms, including some black lines on his Cloth.
Shun wears the new version of the Andromeda Bronze Cloth. It has received a new upgrade since he last wore it, changing the shoulder plates to more pointy ends, adding green emeralds on his Cloth. His chains also received a green emerald color.
Shun's plain clothes consist of a grey sweater, white pants with red straps, black boots. While he traveled as a doctor, he also wore a brown cloak with a hood.
Nebula Chain: His most basic attack, where his chain rapidly slice and wrap themselves around his enemy, capturing them. He can also use it to hit his opponent very hard, and wound him.
Shun has a more powerful version of the attack, and that is Thunder Wave, where the chain go in a lightning-shaped movement, and attacks his enemy with 10 000 volts.
Rolling Defense: Shun used this the first time against Jabu, and wherever he attacked from, the chains quickly took care of him. Shun mostly use it to wrap himself inside a rolling chain, which defends him from all kinds of attacks.
Nebula Stream: He rarely uses this technique, because the result of it might kill his opponent. Nebula Stream connects directly to Shun's Cosmo and entangles his foe with streams from his Cosmo, and paralyze them. Whenever Shun increases his power, so does the Nebula Stream and in the end turns into a Nebula Storm.
Nebula Storm: By the time Shun excecutes this technique, his Cloth is gone (either destroyed or removed voluntarily), allowing him full access to his Cosmo. But because of it's destructive nature, Shun has only used this attack as a last resort. Shun used this technique against Surtr while keeping his Cloth on, indicating that he has learned to access his full power while wearing the Cloth. He also tried it against Aegaeon, but the Class 1-Pallasite neutralized it before Shun could use it.
- Shun is presumably 38 years old as he was 13 in the original series, and 25 years have passed in the era of Omega.
- In spite of his past experience in battle, Shun is still easily underestimated because he does not want to kill his opponents and thus do not fight at full strength.
- Shun is the only Bronze Saint who has fought with his Andromeda Cloth before it evolved into a New Cloth.