It could be that the new person has arrived with higher standards than you and others who've been at the firm a while are accustomed to in your work. Or it could be that they just have different standards which they see as being distinct and higher but that you don't. Or it could be that the new person is better at stating their mind and giving open feedback than has been customary in the past in your firm's culture.Either way, I'd recommend that you don't lose your self-confidence (after all other people appear to have spoken well of you in the past). However, this sounds like a good opportunity to learn - by working with this person you can raise your game and pick up a whole new raft of consulting skills. At the least, you can learn how to work with this new person.You've not mentioned what others' experiences of working with this person have been like, but the likelihood is that this "unfair and unjustified" criticism isn't personal. The way that reputations work is that once one person in your old workgroup endorsed you, others became more perceptive of your good work and reinforced the perception. The new person has not seen any of your good work yet and has not been exposed to the group expectation that you are a high performer - therefore, they need to be impressed afresh.It sounds like you're relatively early in your career so I'd recommend that you treat this as an opportunity to learn from this person's experiences about what consulting looks like outside your present firm. It's worth being cognisant that when consultants enter a firm in this manner, it's often because they've been hired with the remit of "kicking butt" and instituting changes that partners and others in the firm don't know how to implement.Some people may look for an easy excuse to externalise the problem, by suggesting that the new person's behaviour is because they feel threatened. However because of the seniority difference, and because they are the new broom rather than vice-versa, this is very unlikely.