Oogi, the wise old man of the Ginga Forest tribe, was in charge of passing the Ginga-powers on to the latest generation of promising youths. Bokku is a cute little nutcase who acts as a sort of page to Oogi, and wanders about the forests bringing things hither and yon. It was Oogi who kept in a pouch the seed that would later become Moku, and passed it to Bokku to carry to the youngsters, just before he turned to stone and sank beneath the lake with the rest of the Ginga Forest.
When Ryouma accidently left the forest boundaries, he met Yuuta Aoyama. The boy had wandered away from the car, annoyed with his father's obsession with finding the legendary acorn spirit (which of course was Bokku, who had been seen more than once about these woods). Then came the attack by the Balban, and Yuuta and his father were saddened, for though they had neither seen nor known of the clan within the forest, they could see the ache of their loss in the five young people who wept at the edge of the lake. Haruhiko Aoyama offered the Gingaman a place at the riding club he managed, Silver Star. They would be able to board their horses there.
When our heroes planted the seed Oogi had sent them via Bokku, it grew quickly into a beautiful, towering tree. Within the tree they met Moku, its soul. Moku was something more than spirit, less than a god. He was their mentor. It was he who helped them recover ancient weapons lost to the Balban in the long ago days. It was he who helped them use their power responsibly. In the last days of the war, Moku died, giving up all of his life-force to protect the Earth from the Balban. Dying, he gave Bokku a seed, which the Gingaman eventually planted after the war was over and done. When it grew, it turned into Moku again, and everyone was ecstatic.
Then one day the lady met this fella... Gouki actually met the lady. Suzuko Mizusawa, Yuuta's homeroom teacher. Gouki fell head over heels the moment he saw that young woman. He wasn't the only one, though. His competitor for her affections was one Shunsuke Kishimoto, but the two men teamed up at one point to defeat the Balban, towards the end of the series. We also briefly met one Hiroshi, Suzuko's big sister's fiance, but there wasn't a good picture of him to scan in. He was significant in the Gouki had thought Hiroshi was Suzuko's fiance, and though grieved saved the man's life during the Balban attack.
Rather less than present, owing to being turned to stone and sunk under the lake with the rest of the Ginga Forest, was the love of Hayate's life, Miharu. The young couple piped together a great deal. She was wise, and loving, and he missed her achingly. At one point Shierinda even tricked him with a doppleganger of Miharu, but he made it through anyway.
One day Hikaru met Shizuko Hattori, a woman who it seemed had decided to become a professional chef and open her own restaurant. She was a fantastic cook and Hikaru adopted her as a sort of mother figure, nasty-tempered though she seemed to be. But she wasn't, really. She was just determined to make it in a competitive field in which being an older woman was a considerable handicap. The Balban monster wanted to kidnap her to cook for the Balban, but our heroes were able to defeat those nefarious plans.
Then there was little Yuuko. She didn't have a mother, and her father's work had taken him to foreign climes. A neighbor lady was watching over her, but they lived out in the woods so her sole companion was her cat. But it disappeared one day. Then one night a star-power gemstone fell from the sky and landed too near Gingat. It turned the great cat into a little kitten! Yuuko stumbled upon Gingat while looking for her missing Mii. When the Gingaman finally tracked down Gingat, Saya chose not to take her companion, as she felt sorry for the little girl. However, the fights with the Balban went on. Yuuko realized she could not keep the Gingat as it was desperately needed in the wars. It was only when some bright person broke the starstone that our Gingat was restored to her normal size. The Gingaman later found the missing Mii, and Yuuko felt much better.
This character was named Misaki Hoshino, and she was a tv idol. She was also a dead ringer for Saya and a lazy, self-centered young woman. They met during a Balban attack, in which Misaki pretended to be injured in order to get out of work. Saya, however, had actually taken a bad hit to the leg. Still, Saya felt guilty about Misaki's injury and took her place filming the show because Misaki's manager begged her to. Slowly, the actress noticed that Saya was working despite being in agony, and began to realize how the two of them compared and felt bad. Thus Misaki and Saya teamed up. When the monster next attacked, it thought it was pursuing an injured Saya through the trees. But it was really Misaki leading the monster into a trap laid by Saya!
This charming fellow, Assistant Professor Saeki, worked for a university and had managed to stumble upon a three-thousand year old Balban miniaturized bomb. It was deadly, active, and Ryouma and Hikaru had only a short time in which to deactivate it! He was dragooned into helping them.
Life has a way of throwing little snags at us. Meet the actual owner of the Silver Star riding club, Ryunosuke Morikawa. He was somewhat less than pleased to find five extra young people with five horses boarding on his ranch and no discernable income from them. Haruhiko Aoyama tried to pass them off as extra help, and so Mr. Morikawa rode herd on them to make certain they were earning their keep. This complicated matters when they suddenly had to go fight a Balban demon. Eventually, under Hayate's rather furious response to his behavior, Mr. Morikawa let up and actually became fond of them.
The arrival of Bull-Black. Kurokishi, a tragic figure, arrived around the 17th episode. The first thing he did was pull a sorely injured Ryouma out of a cave where a bomb had exploded. Our heroes had some difficulty at first, for they thought he might somehow be Hyuuga... well, eh-hem. He wasn't. He was a soldier from a world the Balban had annihilated, three-thousand years earlier. 
They killed his baby brother, Krantz, in front of his eyes, so he was more than a little off his rocker. Obsessed with defeating the Balban by any means possible, he ran afoul of our heroes who found they had to protect civilians from Kurokishi. However, the problem was eventually solved for them simply because he was dying. But the thing was, he had fallen into a rift in the Earth and remained, barely alive, in a kind of stasis, for thousands of years. When Hyuuga fell into the same rift, Kurokishi caught the falling man and kept him from dropping into the lava. He transferred into Hyuuga's body and used the Earth power to get himself out. He would not long survive the separation from Hyuuga, so he kept our beloved unconscious within him. But Hyuuga fought in dreams, especially when Ryouma's life was at stake. Eventually, Kurokishi sacrificed his life, first by releasing Hyuuga, then by walking into a font of magic power to seal it. Hyuuga inherited his power and weaponry.
This here is Masami Kinohara. Morugumorugu took the girl's body, and tried to trick Hyuuga with it. Saya was not plesed with Hyuuga's interest in the girl, but she tried to put it aside. Hyuuga bought a flower, and Saya came to warn Hyuuga that the Balban were still attacking. But when he asked her to return and gave the girl the flower after splitting the stem, it hurt. But Hyuuga knew what he was really dealing with. The demon tried to poison him, and thought it had succeeded, wearing the girl's body. Saya had exchanged the poisoned juice for a clean batch, understanding Hyuuga's message with the flower. Masami was safe, after Morugumorugu foolishly abandoned her body.
Yuriko and Ichirou Morimoto, a charming younger sister and older brother. They worked in the field of motorcycle racing, and had the fun and excitement of working on a cycle for Ryouma. They were associates of Yuuta's and instrumental in the defeat of Merudameruda.
Kyouhei Okumura, 11 years old and terrified of his own shadow. Well, more of heights. Saya befriended him during the battles with Deathface. He overcame his fears in order to retrieve the berries that would save everyone from Deathface's deadly masks.
She really isn't a ghost or monster, it's just bad lighting. No, Shinobu seemed to be something close to a massage therapist. Yuuta called her in one day to help Saya. This occured during the time period wherein they had lost Hyuuga to Pukuratesu's machinations, and Shinobu it was who gave Saya reassurance and encouragement in regards to Hyuuga.
Why bring a villain into this, you ask? Well, he stood out from the rest. Degiusu was one of Battobasu's creatures, but he was far more than his commander. Once he had been a soldier in defense of the stars. He was still a warrior-born, putting honor ahead, and he became quite fond of the Gingaman he was most up against, Hikaru. But life (or death) struck again. He passed his sword on to Hikaru, and died I believe fighting the Gingaman.
I missed this episode, so the explanation I'm translating is a bit tricky. This little girl is Sumire Hakusan. Maybe. The important thing was that either she, or a flower she had, was a flower fairy. This was Saya's adventure, and it seems she needed help, needed her power enhanced when fighting Chainsaws! And they won, naturally.