That Nobunaga was called “Owari no Ooutsuke (big fool from Owari)” when he was young since he behaved weirdly. A biography about Nobunaga, “Shinchou Kouki (信長公記)” written by Oota Gyuu-ichi, who was one of Oda Nobunaga’s officers (and later one of Hideyoshi Toyotomi’s officers) around 1610, tells what happened at his father’s funnel. His father, Nobuhide, died in 1551. Nobunaga came to his funeral late, and threw incense at the altar in disrespect. This drove his mentor, Hirate Masahide to commit seppuku out of shame. Except this, Nobunaga wore Yukatabira (which is usually worn as pajama from everyday life), tied his hair with colorful string without topknot, used a rope instead of a belt hanging several gourds, and waraji. His strange fashion let people think that he is strange or crazy. However, today, people interpret it that he was actually very smart and just pretended being foolish.
Very often it is said that Nobunaga loses his temper very quickly and was very merciless like some episodes show. There’s a saying he might have said what to do if a mockingbird refused to sing for him: he would kill it. When he set to Enryaku-ji Temple on Mt. Hiei, around 4,000 people were killed including women and children. At the Sieges of Nagashima, there were more than 20,000 casualties.
Those who do not obey are excusedly and completely eliminated, regardless of how they are, whether they are monks or women or children, and are conducted as extremely devilish people.
His nervousness and suspicion were strong, and he responded particularly violently to acts such as betrayal, so his younger brother, aunt, etc. seemed to have an immoral character that would take mercilessly life inside him.
On the other hand, there are some episodes that tell his thoughtfulness for the weak. According to Shinchou Kouki, Nobunaga met a disabled person called “Monkey in the mountain” who lived in the mountain as a beggar along the road when he was walking in the middle of the mountain at the border between Mino and Omi. Every time seeing this person, he comes to think deeply and let the people of the village gather 20 cotton rolls to exchange them with cash so that the “Monkey” can build a house. Nobunaga also told the people to give food to “Monkey”.
Nobunaga might have held great compassion and sought to be of service to others and been capable of giving comfort to those in need.
Also, it’s told often that he may have been pretty open for new things. He actively tried to incorporate European culture. The reason why he tried to adopt Christianity is for ex., import of European techniques and goods in “Nanban trade” (Southern barbarian trade), bringing Christian missionaries, and keeping a part of Buddhists (such as the uprising of Ikkou-shu) in check. In the Nanban trade, many things such as guns, western clothes (hats, leather jackets and boots), oil paintings, globes, and western instruments (organ violas). have been introduced to Japan. It can be said that the Christian tradition helped his dream of unity in the Japan.
He was merciless and unforgiving to the opponents, but friendly and kind to the vulnerable members of society, and willingly adopted new things.