The major reason why he began to hate the realm lord is because of the theft of life essence from the high life plane by demons. The demons didn't destroy the life trees. They just took their flowers but that was enough to make him angry at the realm lord. Now he knows he was being naive and ignorant back then. His thoughts and opinions of the realm lord don't matter without the strength to effect the change he desires. And the changes he wanted back then we're stupid too.
Maybe he could have stopped the Invasion of his plane by demons if he had the strength to. But he would have faced a lot of opposition from the other powerful high elves even if he had the strength. It is not like there is no one in the entire plane or across the entire ancient history of high elves who didn't know what the realm lord was doing by allowing demons to attack them.
The fact that he didn't know back then doesn't mean no one else didn't know. So other high elves knew about it, but that didn't change their opinion of the realm lord and neither was it enough for them to stop the invasion either. It is mostly because the realm lord was doing more good than bad. The invasions allowed the elves to fight and experience war in a controlled situation. In fact, no Sovereigns participated in the war. The demon lords that invaded would have stood no chance against a Sovereign of law.
So in retrospect, it is obvious that the highest authorities in the plane were aware of what was going on but didn't interfere. The high elf council used the war to strengthen their population and eliminate weaknesses. It is similar to what the battle sage monkeys do when they send their youths to the ancient battlefield to participate in the trial of heaven.
The realm lord has done a lot of good for high elves already. He is a legendary figure that will never be forgotten as long as high elves exist. The ban on the exploitation of life trees is the most important achievement of the realm lord. The realm lord had to offend a lot of people when he stopped the exploitation of life trees. There was a war that shook the realm anand the plane of high life but he won at the end of the day. But it turns out that his glorious act will one day come and bite him back.
"Is it that bad?" Soverick asked. "I mean, it was such a long time ago and life essence has no use to origin gods much less world gods."
"The fact that you asked that question shows that you're not that old and that you don't know the full requirements of becoming a world god. That means you are not a world god yourself or are not related to one." The sage said. "So how did you come across the information about the realm heart?"
That question sobered up Soverick. He remembered that this is not a meeting between friends. Each of his actions and words are examined for further information about him. His seemingly harmless question has clued the first sage in that he doesn't have a close relationship with a world god.
He didn't let that fluster him. He defended his ignorance without shame. "It is true that I am very young and if you haven't noticed, I haven't met the first requirement to become a world God yet. I don't have a supreme law. I will ask mother high heaven when I am ready. That's how the first world gods knew how to become world gods and probably how you found out too so there's no reason for you to feel smug just because you were born thousands of origin cycles before me."
He is very young but he doesn't feel my shame because of it. He is less than 10,000 years old while Legion-1 is about 8 origin cycles old. Ghoto and Mihila are tens of origin cycles older than him. The sage on the other hand is multiples of thousands of years older than him.
He has achieved a lot in the little time that he has lived and he is here talking to a world God face to face. His parents will never achieve what he has achieved and some Origin gods have never met a world god. That is more than enough for him to be very proud.
The eye of the sage looked down on him with a condescending gaze similar to the one you would give an ignorant child.
He continued, "When you have lived long enough you become able to wait and bid your time. Having all the time in the world means you can plan for the long term. Patience is a virtue that all eternal existence will learn in time. That alone is enough reason why I have the right to be smug. If you had it, then you wouldn't have asked that question."
They stared at each other with neither one giving ground.
The first sage continued, "The realm lord's offense was not forgotten. It was only shelved for a better time when he will be pressed, desperate, or pushed against a wall. The era of conquest happens to bring his enemies this opportunity. His offense is so great that he has enough enemies to drown out the realm of high heaven. You may find it difficult to imagine how great of a sin he committed due to your young age and its accompanying ignorance so I'll show you how important life trees are."
The sage brought forward the crystal gem with infinite faces. "This is the world seed. It is the foundation of life in a world. It is the seed that becomes the tree that you see. The world spark gives it form and direction while the living things within the realm give it a consciousness. That consciousness is known as the Will of the Realm."