Circular systems with adjacent alliances and complementary opposites are the best :D
Originally I was going to have Iron oppose Night and something-else because Iron is concrete and Night is abstract, but the more I think about it, if Iron and Summer are connected by
heat then Winter should probably oppose that pair. But I do like your Withering for Autumn and Winter... hmmmm...
Okay. So:
Spring (nature, healing, renewal) opposes the Autumn-Night pair, which I haven't named yet.
Summer (fire, light, energy) opposes the Night-Winter pair, which I have designated
Sleep.
Iron (metal, engineering, durability/solidity) opposes the Winter-?? pair, which I haven't named yet.
Autumn (characteristics unknown) opposes the ??-Spring pair, which I haven't named yet.
Night (darkness, dreams, death) opposes the Spring-Summer pair, which I have designated
Life.
Winter (cold, something something?) opposes the Summer-Iron pair, which I have designated
Heat.
And the mystery element opposes the Iron-Autumn pair, which I have designated
Strength, but I might change that if I figure out any characteristics for Autumn.
Here's a link to my scratch work.
I don't think "Dew" works anymore for the mystery element, but I do know I want to hide some traditional elements in among the specialties of this set - like fire under Summer, metal under Iron, nature (i.e. some interpretations of earth) under Spring... I wonder if there are particularly good places to put air and water? Autumn or Winter have room to take some, and I suppose it makes sense for Winter to take
ice... hmm hmm. Thoughts, anyone?
Actually, what am I saying, water should totally go to Spring. It's even a pun! So Spring is now nature/healing/
water ('renewal' was basically redundant anyway). So that opens up some more options for things Night and Autumn can share, I guess - note how Summer's 'energy' aspect complements Sleep, Night's 'death' complements Life, and Winter's 'cold' complements Heat; I like things to line up nice and tidily like that. Presumably the mystery element has an aspect that complements Strength, unless I can't figure one out, in which case I guess Iron and Autumn can share something else.
edit: I have now designated Autumn/Night as
Fear, opposing an aspect of Spring's 'healing'. And I gave Autumn "work, wealth, spirits" as aspects, but I don't really like the words; I don't think they encompass what I was going for. ('Work' as in the labour of the harvest - accomplishing physical tasks. 'Wealth' as in the
bounty of the harvest, extended to the general concept of material goods. 'Spirits' as in the common concept that the autumnal equinox is a time when you get to talk to dead people. Spirits is the weakest, I think, but it's also the link I'm making to Night through Fear, so... idk? Can anybody dig me out of this?)