During my personal Lost rewatch I followed Episode 14 in Season 1 with the title "Special" - it's a Walt centric episode. Well like the title says, Walt seems to be a key element in the life-death circle. Walt has been discribed as "different" and "certain things are happening around him". Walt seems to be the aura of death.
- in S1E14 Walts mothers' condition gets worse; she dies one week later - at the same moment Walt is learning in a book about Australian birds; the picture he is looking at shows the bird that died a few seconds ago - Libby and Anna-Lucia had to die during Michaels rage against the Losties; Walt was kidnapped - When Locke was shot by Ben and lying in the Dharma-Purge-Hole nearly dying, Walt appeared and disappeared again - Right after Locke visited the Oceanic6 off-island with Walt as last station, Ben kills him in the appartment.
We have seen Jacob "reviving" Locke after his fall, so Walt clearly seems to be the opposite of him.