Yeah, that is an interesting angle. Which is the cause and which is the outcome?
I guess there are two types of fear of death. The sheep mostly fear the event of death itself and the emptyness afterwards. While the tyrants more often fear not so much the event of death, but rather not acomplishing something before death. Dying too early that is. That is totally irrational, because who cares about anything after you die, but it is like they are endebted those accomplishments to someone. And subconciously they probably are. It seems this is how brain works: it needs a reason for everything until at some level it stops challenging the reasons. So I may agree, that this type of fear it is fair to call ego, because the brain does not remember who it is endebted to, so it basically is endebted to itself. And then fear is more a result of this debt rather then vice versa.
I keep trying to deduct ego because it does not seem to be natural. No other animal has it. They fight for resources and females. In some cases it looks like they fight for status, but that is motivated only by getting access to females and food. They do not care what other members of the gang do, where they go, they do not try to remind their status to anyone as long as their access to food and females is unobstructed. They also do not look for even better nor different females in other gangs. So they are not endebted to anyone, they just live in the moment.
This irrational behaviour turns them both, tyrants and sheep, into preditors on their own kind, which destroys the harmony of nature in everyone impacted. Harmony of nature is happinness, so they destroy happiness.

There is always truth and new discoveries in discussion. 🤜🤛🏾
Let's do it again sometime.