[Yoda9864]

The encoded message would look like this if the keyword was Mario:

ql di ci id lr gh fr rp ol ql bi pt ka rz ma za ik cx lc id ar io ru rc yb lu so dt qi ld tg ch dy ci hq lr gh fr ag rq ey ur zh ar vb ri om hc hf na ru ci lz im rc fp ui lu lc ar qu lc id ri ci ni ui bu mo lu tu qc yi fz hc lu qm xr tr ez fz fr lu eh ci ir ho eq om ku df lf iq ql dt qi is fn ql bl ra li fz lb ue my bt hi il dx ql fl po cf im bo ri om xd bi ro lo gh ya ky ge dt na zh ol ql bl ra ly lc id ri bt hi df qx lc id zi qf oh lb uq az di pq ey bi qr kf by fl lb yl ys ir ar io ru pq tx fz op tu lb sy ql di iz ih ar lm ha oh kx cm dh do ma fm xq di qd la ke id kz

We would have to manually put the numbers in, fix all of the spaces to make it look like it's a straight up cihper:

Qldic iid 8 lrghfrrp ol qlb iptkarzm azaik cxlci dario’r urcyblusod tqil dtgch. Dyci hqlrghf rag rqe yur zha. Rvbri omh chfnar uci lzim, rcf pu ilu lca rqulc idr I cin iu ibumol utuq cyi fzh’c luqm xr tre zfz’f rlueh ci irhoeq omkud. Fl fiq qldtq ii sfn qlblr, ali fzl buem ybthiil (dxq lflpoc fi mborio mxdbirolo (4) ghya ky gedtn.) az hol qlbl rally cid ribthi dfqxl cid ziq foh lbuqa zd ipqey biq rkfb yfl lbyly sirari (1-oru.) pqt xfzo ptu lbs yqldi iziha rlmha ohkx cmdh domafm’x 7 qdiqdlak eidkz