Redmane Knight Ogha is one of the many spirit summons within Elden Ring, he is also part of the Legendary Ashen Remains.
In order to acquire Redmane Knight Ogha you will have to face a mighty foe, he will then become one of the rewards.
FINDING REDMANE KNIGHT OGHA
In order to find and obtain the Redmane Knight Ogha summon you will have to travel to the War Dead Catacombs. It is south of Lenne’s Rise.
Whilst in the War Dead Catacombs there will be a boss that you will want to find and defeat, this boss is known as the Putrid Tree Spirit
Defeat the Putrid Tree Spirit and you will get the Redmane Knight Ogha as a reward
PUTRID TREE SPIRIT
The Putrid Tree Spirit is a rather large foe that enjoys moving around a lot. One of its attacks is a fire attack, which can incinerate the area around it.
It also has other moves that it enjoys doing too such as using its fists and performing a lunge attack. However, one of its weaknesses includes using magic so take advantage of this if you are a caster class.