The Jonjo O'Neill-trained Minella Rocco, runner-up in the 2017 Timico Cheltenham Gold Cup Chase, will shoulder top weight, with Noel Meade's Road To Riches sneaking in at the bottom of the 40-runner field set for the Randox Health Grand National Handicap Chase April 14 at Aintree.
Gold Present was the only withdrawal at the final 48-hour declaration stage for the the historic, grade 3 race.
Blaklion is one of two runners for Nigel Twiston-Davies after he finished fourth in last year's race, and he will be joined by stablemate Double Ross.
Gordon Elliott will aim to cap a terrific season with Tiger Roll, Ucello Conti, and the 13-year-old Bless The Wings.
He is not the only teenager in the race, though. Fellow 13-year-old Raz De Maree will try to supplement the Coral Welsh Grand National Handicap Chase he won in January when he was ridden by James Bowen.
This time, Bowen rides Shantou Flyer for Richard Hobson, while his elder brother Sean will be on Warriors Tale for Paul Nicholls, who also runs Vicente.
The Last Samuri, trained by Kim Bailey, was second to Rule The World two years ago and unplaced last year. But Bailey was delighted with the 10-year-old gelding's third behind winner Tiger Roll in the Glenfarclas Chase (cross country) at Cheltenham.
"I'm very happy with his preparation, and I thought he ran a fantastic race in the cross country," Bailey told At The Races.
"He's as good as he was two years ago. But, unfortunately, he's carrying nearly a stone more than he was then, which makes it difficult."
Total Recall, Gold Cup third Anibale Fly, Seeyouatmidnight and Baie Des Iles are other contenders. Baie Des Iles is racing for the husband-and-wife team of trainer Ross O'Sullivan and jockey Katie Walsh.
Bryony Frost will ride in the National for the first time when she is reunited with Milansbar, on whom she won the Betfred Classic Handicap Chase at Warwick in January.
Rachael Blackmore will also ride over the Aintree fences for the first time as she has been recruited by Mouse Morris to partner Alpha Des Obeaux.
The four reserves are Thunder And Roses, Delusionofgrandeur, Walk In The Mill and Vintage Clouds. If any of the 40 confirmed runners are taken out before 1 p.m. (local) on Friday, the reserves will step up in the order in which they appear on the race card.