What is happening behind the scenes when one is “consumed by hate?” This appears different from nursing a grudge as it implies something happening “to” a person, as opposed to something they are actively embracing and knowingly contributing to. What is Creator’s perspective?

This is a distinction of degree rather than kind. When one is consumed by hate, this implies not only is there hatred present but it becomes not only a high priority but an important agenda for the person to take action, and often repeated action, to, in effect, go to war against their opponent and look for ways to fight back and cause them harm. Most people have many things they choose to let go of rather than fight each one. There is wisdom in this because one can gain enough inner strength to be impervious to attack, in a sense, so that being opposed, being denigrated, being cheated, being rejected, being abandoned, will not be seen as a wound to the self as much as a karmic misstep by the attacker that shows their poor character, and that they are to be pitied more than despised. So being consumed by anger is being on a path of destruction. Most people will fear for the opponent in this situation, when the reality is both the opponent and the one consumed by anger are in peril, because holding hatred and acting on hatred wounds the self in parallel and will incur a karmic penalty that will be double, because the one acting in hatred must rebalance the harm to their victim as well as to themselves. So we would say the characteristics of being consumed by hatred are very much a sign the person is in dire need of healing. Even when there is righteous anger because the person consumed by hate seems to have full justification, for example, because of the magnitude of mistreatment, "Two wrongs do not make a right," and as we have said again and again, "Fighting fire with fire makes the victim a perpetrator in their own right and they are joining ranks with evildoers when they give in to the impulse to harm others or the self, even through holding such thoughts." We understand this is a high standard, but aiming for being lofty will carry you further than giving in to negative thinking and acting on impulse that might make things much worse and create future burdens in the bargain you will need to clean up.