Energy in physics feels analogous to money in economics. Is a manmade medium of exchange used for convenience. It is the exchange medium between measureable physical states/things.
Is energy is real in the same way money is? An incredibly useful accounting trick that is used so frequently it feels fundamental, but really it’s just a mathmatical convenience?
Small aside: From this perspective ‘conservatipn of energy’ is a redundant statement. Of course energy must be conserved or else the equations are wrong. The definition of energy is it’s conservation.
People have died from energy. So, no.
You could die from nuclear radiation, micro waves, electricity, heat. These are all energy.
All those things have energy, but they aren’t energy. For example, with microwaves the energy is proportional to the wavelength. Nuclear radiation comes in 4 forms, three of them are fast moving particles, one of them is photons. Energy allows us to say this light wave with a specific wavelength has the same amount of energy as this beta emission electron with a specific speed, mass, and charge.
People died from the interaction small wavelength photons imparting momentum on the atoms on their body, or fast moving particles colliding with the atoms in their body.
If someone fell off a building and died I don’t think anyone would say ‘energy did that’. The person died as a result of transferring a lot of kinetic energy to the ground though.