What does it mean when roger felt the taboo of the old life also what does it mean when jack approach roger and a darker shadow crest beneath rogers skin what effect is jack having on roger?

When Roger felt the taboo of the old life, it means he was starting to embrace the savage instincts that were suppressed in their previous society. When Jack approached Roger and a darker shadow crested beneath Roger's skin, it implies that Jack's violent and aggressive nature is influencing Roger to unleash his own inner darkness, leading him to become more brutal and ruthless in their new savage society.