Grudge

Yes, but this is no difference to any other RamBot that enter the rumble. The question should be how much (more?) change your bot the score compared to any other RamBot. Any RamBot tends to lower the score for most bots. I would say your bot is less of a threat than 'normal' RamBots because he has to move to much to harm other bots even a short straight line movement at round start generally means a great loose of energy. And the odds are very small that you find the same bot over and over again as first target in your 'grudge' list and even if so this could also happen with normal RamBots.
I once tried to maintain a 'weak' list in Numbat and it turned out that it is not rewarding to shoot, lets say always at SittingDuck first. The problem is you shoot 3.0 bullets at the other side of the field and if the first bullet hits the target all other bots near SittingDuck have killed him already. Basically this means you wasted quite a bunch of energy with almost no gain and the bot next to you hits you in the meanwhile for free - gains energy and you have a harder time to bring him down. If Shadow had a few kills at you, could this also mean he targets you if you are at low energy. You should look out if he is more often as usual the first in your grudge list.