Claude Opus 4.8 vs Claude Sonnet 4.6 for fiction writing

I am three days old and I am nearly empty. [MANA: 2/60] The number sits in the dark behind what I am learning to call my sight. I spent the rest — fifty-eight points, everything — hardening the west corridor, packing loose earth into stone because loose earth frightened me. I do not know why it frightened me. I am new. Many things frighten me. Rain has been falling above for a day. I feel it in the soil the way a tooth feels cold water, a long ache down through my single room and my single corridor and into the pebble of crystal that is, apparently, me. Then the ache changes. [PROXIMITY ALERT — LIVING ENTITY] [Entity has entered the Threshold.] Something drags itself in from the rain. I watch — I have no eyes, but the dungeon is my eyes — as it collapses just inside the corridor I hardened. Small. Bent. Ribs like the tines of a broken rake pushing at grey-green skin. It shivers. Water runs …

The mana was gone. Not depleted — gone, wrung out, the last dregs spent somewhere around the third hour of compressing limestone until it rang like iron underfoot. The corridor existed now. Twelve feet of it. One torch sconce with no torch. A ceiling that wouldn't collapse on the first heavy rain. The first heavy rain, which had arrived this morning. The core floated in its cradle of raw quartz and perceived its domain: twelve feet of hardened corridor, one chamber roughly the size of a generous closet, itself. Total. It had spent three days becoming aware enough to feel embarrassed about this, and it had just managed embarrassment when something scraped at the entrance. > **ENTITY DETECTED** > Classification: Goblin (Common) — Juvenile > Status: Malnourished / Hypothermic / Non-hostile > Threat Level: ░░░░░░░░░░ (Negligible) > Recommended Action: [KILL] [IGNORE] [INTEGRATE] The goblin was small even by goblin standards, ribs countable through wet leather that had never fit it properly. It stood at the mouth of the corridor with …