Rounding up: I really want to pick on your tense problems. As long as you aren't quoting the direct thought “I will do X”, then you
need to stick to your chosen time, and there was a significant number of errors on this count. “Merlin
would do X”. Make use of all the past tenses available to you and you ought to be able to convey everything.
I particularly noticed a lack of pluperfect: “before he did this, Merlin
had done this”, and what I believe is the conditional perfect in technical terms: “before this happened*, Merlin would have done this”. Between your current point in the past and a later anticipated point in time.
*strictly speaking, in the case that your anticipated event is counter-factual, this could be 'were to happen'. In practice, it will be “before this happened” no matter the likelihood of the event.
No-one will say 'were to happen'. Except maybe me.