|4-Kanji Translation:||The Unexpected Leap|
|First Appearance:||Sengoku BASARA 3|
|First Playable:||Sengoku BASARA 3 Utage|
|Voice Actor:||Christopher Smith|
Mogami Yoshiaki, the leader of the Mogami clan that rules Dewa Province. Often known as "the Noble Fox of Dewa", though he is referred to as a weasel in the overseas release. He thinks of himself as a great and smart nobleman. He appears as a thin and tall man, often holding a cup of tea, with a rather wacky moustache. While he is Masamune's maternal uncle, the two of them rarely hint at it, though Yoshiaki refers to him as "Masamune-kun".
He often tells his opponents that he has prepared tea, as a welcoming to their visit. However, he also has a habit of not remember his opponents names and talks down to them as he attacks.
Yoshiaki will always join the Eastern Army, no matter which story is being played. To do this, he appeals to Ieyasu and forces Maeda Toshiie to ally with the Eastern Army as well by kidnapping Toshiie's wife Matsu in order to ensure his compliance. When the player fights Yoshiaki at his stage in Hasedo and defeats him, they will also free Matsu, provided they are not playing Masamune's paths.
Yoshiaki is one of the eight characters to receive their own story in Sengoku Basara 3 Utage.
Mogami Yoshiaki (最上義光) was a daimyō of the Yamagata domain in Dewa Province, in the late Sengoku period and early Edo period. He was the first son of Mogami Yoshimori, and succeeded his father as daimyō of Yamagata. He also was known as "The Noble Fox of Ushu/Dewa" and has a mixed reputation in fictional sources. He is sometimes be depicted as a wise ruler or as a villainous man who didn't fight at all.
When Toyotomi Hideyoshi came to power, Yoshiaki submitted to his rule, but later became a supporter of Tokugawa Ieyasu following Hideyoshi's death. He was known to hate the Toyotomi due to the fact that Hideyoshi ordered the execution of Yoshiaki's teenage daughter when purging his nephew Toyotomi Hidetsugu, whom Yoshiaki's daughter was engaged to.
In 1600, he battled Uesugi Kagekatsu, an enemy of Tokugawa's, alongside his nephew Date Masamune. He aided in Date's siege of Shiroishi, and was then attacked in his own home castle of Hataya. Later that year, Mogami and Date supported Ieyasu at the famous battle of Sekigahara, after which Mogami's domain was expanded to 520,000 koku in return for his loyal service. This made the Yamagata domain the fifth largest in Japan at the time, excluding the land held by Tokugawa. He died at Yamagata Castle in 1614.
- Skill 1: Yoshiaki swings his sword along the ground before jumping off the ground in midair to do a rapid thrust attack on you. If he makes it through, he lands safely and asks "How am I?"
- Skill 2: He cowers in fear while begging for his life. He then grovels and trembles. If you try to attack him, Moygami will retaliate with 2 rapier swings that cut you.
- Basara: Yoshiaki first holds the end of his sword as he stomps the ground then starts to do a spin attack as he covers himself in a tornado. After a few spins, Yoshiaki becomes dizzy then regains his stance and bows.
- The Mogami Clan, at one point, clashed with the Date and Uesugi Clans.
- Yoshiaki is the uncle of Date Masamune.
- During his stage you have to destroy his riverside bases to stop the cannons from shooting down your ship (which will attack the main base).
- In a few of his moves, Yoshiaki seems to support himself on his sword, a stance similar to that of Yoshimitsu (From the Soul Calibur and Tekken series).
- Yoshiaki can be unlocked as an ally after being defeated in Date Masamune's path.
- He owns a falcon named Starlight Starbright – a bird which is commonly seen during Kuroda Kanbee's cutscenes as it steals the key to the cuffs locked around the man's wrists.