'climactically' originates from Greek, specifically the word 'klimax', where 'klimax' meant 'ladder' or 'a series of steps' (used metaphorically for a high point).

'klimax' (Greek) passed into Latin and then into English as 'climax'; the adjective 'climactic' was formed from 'climax' + '-ic', and the adverb 'climactically' was later formed by adding the adverbial suffix '-ally'.

Initially connected to the idea of a 'ladder' or sequential steps, it came to refer to the 'highest point' or 'culmination', and now 'climactically' means 'in a manner that forms or relates to a climax'.